browning bpcr accuracy

[bigted]

ive written about this rifle a few times and still the accuracy escapes me/it.

the rifle is an early model browning bpcr 45-70 with the half oct//half round 30 inch barrel. the hiwall action is color cased and the extractor is that...not the ejector.

little history is this...

ive loaded cast boolits in 520 lyman...430 lyman...540 rcbs g/c'ed... i have sized them to the .459 which is .001 over groove of the barrel. ive loaded also Remington 405's...hornaday 300's...hornaday 350 round nose as well as flat nose jacketed bullets. ive used cartridge black powder in various grains from 58 to 72 grains in cartridge as well as 2f both Goex... also loaded rl-7 in my favorite 34 grains with cm filler which is very accurate in my other bp style rifles as well as a ruger #1 and a marlin lever...no go...ive loaded 3031 and unique as well as 4064 in different grains..... ive used large pistol up thru mag rifle primers in cci as well as federal and remington primers.

i got this rifle second hand and know nothing about the history of the rifle itself. the only thing i have not fooled with is the rifle...sight wise it wears a 6 thru 18 power Leopold which is a known good scope. i have proved it on other rifles so know it is good. next i plan to have a new crown done on the barrel...this one is the flat recessed style that defies cleaning the sharp corners in the well it lays in.

just looking for ideas for this rifle before i have any metal work done to it. have i missed a step here???

oh yea...accuracy is thusly.......2.5 inches at the very best at 100 yards. ive gotten at worst a 7.5 inch group with the 430 lyman with black powder of 72 grains...cartridge Goex.

ive shot pounds of powder thru this in bp as well as smokeless.......primers by the bucketfuls and always shot fron a bench-rest to remove me from the equation. ive found the "node" on the barrel and rested it there and also thinking i had a bad fit on the fore-arm i removed it so it had no bearing...no avail. trying to remember everything in sequence as i methodically have approached everything ive done in the search for the equation on this rifle.

any ideas would be welcome...even the ones ive tryed and maybe done in a way that could be improved. the re-modeling of the rifle is my last step...hope ill find an answer so it wont cost me an arm n a leg in smith work.

[littlejack]

Hey to ya bigted:
I will give you the load that I use in my Uberti Hiwall 45-70, you may do as you wish with it.
The ONE thing that caused my groups to shrink drasticly, was seating the boolit shallow enough to allow the front driving band to be engraved by the lands. This left one whole grease groove exposed on the finished cartridge. I tried multiple times to load and reload the cartridges the way I wanted them to look. BAD IDEA. I was getting fair groups but none that satisfied me. I was told to seat boolits to kiss the lands but figured I could make the rounds/rifle shoot without exposing a full grease groove. I did/could not. The rifle likes what the rifle likes.
Here's the load.
I cast the 457125 Government boolit with 20-1 alloy.
They fall out at 522 grains.
I size them in a .459 Lyman sizer. This does not take off much material.
I lube with Emmert's recipe.
I use WW brass, neck sized only.
I flair the neck, so as not to shave the boolit upon seating.
WLR primers.
70 grains of Goex 2f powder, dropped and vibrated.
One .040 card wad on powder and one newsprint paper between card wad and boolit base.
Compress all to .600 below case mouth.
Seat boolit to touch the wads.
Crimp just enough to take out case flair.
In my rifle, this load will shoot one moa at 100 yards with 5 shots.
My rifle barrel has a 1 in 20 twist. Yours probably has a 1-18 twist.
Good shootin to ya.
Jack

[NickSS]

You did not mention amount of compression of your BP loads. I have found that each of my rifles like a different amount of compression to give optimum accuracy with BP. If you have not done so already try varying the amount of compression you give the load.

[excess650]

Check the throat and see if its concentric. I knew some guys who bought the Brownings when they first came out and it appeared that the throats were off center. I suspect an undersize pilot on the chambering reamer was the culprit.

One of the rifles was REPLACED by Browning and was later seen on the clearance rack at a Browning dealer/distributor with the same barrel. It was identified by its PO.

[Lead pot]

The rifle is telling you that it does not like the short bullets.

[kokomokid]

My shooting partner has one in 40/65 that is way off concentric in the bore. Dont know if any 45/70 were cut that way, You can see it plainly and making a hammer chamber cast leaves no doubt. He shoots in the top 5-10% at most of our BPCR shoots. I think his solution and only way it would group was a heavy bore rider jumped .030 to .050.

[BruceB]

[QUOTE= It was identified by its PO.[/QUOTE]



What in blazes is a "PO"??? PLEASE don't use abbreviations that you ASSUME "everyone understands".

[bigted]

little jack...ive loaded this exact load minus the set-out to the rifling...it was the best load so far and it is the 2.5'ish load i mentioned...ill try the setting out to the lands and see what it does...thanks

nickss...the different loads of black powder have different compression value for the boolit to seat so this has been the compression on each grain load of black powder...dont know how to change the amount of compression without changing the amount of powder charge.

lead pot...i agree with the short boolit thing. i have settled with the 457125 boolit that also drops from my mould at 522 grains and i run them thru my lyman sizer at .459 for lubing/sizing...does not hardly rub the boolit so i think they are pretty close as cast. the rcbs did very badly in this rifle...the 45-500 mould gas checked.

have not checked the throat as of yet...guess i should cast the chamber/throat to check where it is all at. ive never done so...could you run the procedure down for me please?

also no mention of the crown yet...any thoughts?

[kokomokid]

Tex mac has a good how to on chamber hammer cast posted somewhere. I grind off about .200 of my brass so I get a good chamber length and dia impression. Be sure and use dead soft lead.

[excess650]

What in blazes is a "PO"??? PLEASE don't use abbreviations that you ASSUME "everyone understands".

PO = previous owner

[montana_charlie]

guess i should cast the chamber/throat to check where it is all at. ive never done so...could you run the procedure down for me please?

If you want to 'cast' the chamber, buy a Cerrosafe ingot and follow the instructions.

If you want a 'hammer cast':
Tools -
- Heavy hammer (2 to 3 pounds is about right ... heavier is okay, but lighter is really not).
- Steel or brass rod that just fits in the bore, wrapped with tape at intervals.
- Pure lead slug. (Perhaps a 457125 bullet rolled to reduce diameter to .450" or less.)

Preparation -
- Shorten an empty case by about an eighth of an inch, for a clean impression of the chamber mouth, itself.
- Fill case with something solid ... damp sand, JB Weld, molten lead, very old wedding cake icing.
- Leave about a quarter inch of empty space in the mouth.
- Lightly oil chamber and throat.
- Chamber prepared case with lead slug shoved up in the throat and close breech.

Procedure -
- Place taped rod in bore with solid contact on lead slug.
- Hit rod with hammer and notice if hammer bounces.
- Hit rod with hammer and notice if hammer bounces.
- Hit rod with hammer and notice if hammer bounces.
- Whenever hammer bounces, stop hitting rod with the hammer.

Aftermath -
- Remove the created 'hammer casting' from the chamber.
- Start searching for your dial caliper.

[bigted]

thanks charlie...sounds simple enough even for me.

[kokomokid]

Thanks charlie. The cerrosafe is not usefull after 30 min or so and the soft lead is a good reference for as long as not dropped. I use a fired brass about 90% full of lead and make sure my fireing pin is back when forming a cast.

[kokomokid]

may want to put an index mark on the brass in case something odd shows up.

[littlejack]

MC, that is some very fine and discriptive information.

[BruceB]

PO = previous owner

Aha! NOW I get it.

I just couldn't get past "Purchase Order" which definitely didn't make much sense, even to me.

Muchas gracias.

[semtav]

Go over to the shiloh forum and send Ken Heier a PM and see what he is using. I think he won the Ekalaka half mile with that gun.

[RMulhern]

The rifle is telling you that it does not like the short bullets.

Lead pot

EXACTLY!

I've had several and shot others over the years and NEVER shot one that didn't deliver great accuracy.....all the way to 800 yards!! This was shooting a 530 gr. Postell bullet with reduced front drive bands to .4495" so I could seat the bullet out and get 80 grs. Goex FFF powder in the case!

[montana_charlie]

The cerrosafe is not usefull after 30 min or so and the soft lead is a good reference for as long as not dropped.
It's not unusual for a custom mould maker to ask for a chamber casting of your rifle so he can fit the bullet to your particular dimensions.

Now, it's obvious that you can't make a Cerrosafe model and get it mailed to the mould maker in thirty minutes. So ... you figure there MUST be a way to get useful dimensions from the casting as it ages.

If you know the math, you can use a casting of any age to determine the dimensions of the chamber it was cast in.

I'm not the mathemetician who figured it out, but I can post the information if anybody is interested ...

CM

[Lead pot]

I have two Browning's one in .40-65 and the other is a .45-70 and they both are good shooters. The .40-64 had one of the screwed up chambers but that cleaned up when I ran a throating reamer in it and changed the 45 degree lead to a 4 degree with a 1°30' that made it a tack driver even with a heavy bad trigger pull.

[Gunlaker]

great accuracy.....all the way to 800 yards!! This was shooting a 530 gr. Postell bullet with reduced front drive bands to .4495" so I could seat the bullet out and get 80 grs. Goex FFF powder in the case!

I've been casting with a new Steve Brooks Creedmoor mould that I've been using in my C. Sharps rifles. It gets (finger) seated waay out. The first two bands are at bore diameter and the next is 1/2 way in between. The base bands are .460" for the large diameter freebore in my rifles. It's by far the best bullet these rifles have seen. It fits the throat diameter in both rifles and is aligned well.

I do happen to have a Browning BPCR that I picked up used at a gun show this spring. I haven't done a chambver cast on that one yet, (haven't had a chance to shoot that much either), but I do know that the chamber needs long brass and it has little or no freebore.

Chris.

[bigted]

just loaded a dummy case with a 125 boolit and kept seating a little at a time till the action closed and just engraved the rifling with the small amount of remaining closure from the breech block. the complete front greese groove is totally out of the case so this means i have been short seating all this time by around 3/16th inch. haven't and wont have time to load n shoot some for a test but this is enough of a hint that it may well be a huge step in the rite direction. to say nothing about the extra amount of powder ill get while doing this.

dont know why i missed this little trick as i have a 25-06 that requires the same thing with jacketed bullets for the accuracy.

i am going to get some pure lead and do a pounded lead mould of my chamber/lead area to see exactly what that looks like as well.

thanks all.......AGAIN!!!

[littlejack]

That is exactly what I found with my loads Ted. I was short seating about .100.
My rifle did not take kindly to adding a whole lot of extra powder either. 70 grains works
great.
Jack

[montana_charlie]

i am going to get some pure lead and do a pounded lead mould of my chamber/lead area to see exactly what that looks like as well.
You are likely to find that the depth of your chamber is considerably greater than 2.1", too.
CM

[Gunlaker]

You are likely to find that the depth of your chamber is considerably greater than 2.1", too.
CM

I believe you are correct based on what I've seen shooting mine. I get a big lube ring when shooting cases 2.10" long.

Chris.

[Moondawg]

You never mention whether during all your testing, if you were shooting with wind flags. If you are not, and you have any wind/breezes, than you do not know if any inaccuracy is a result of load/rifle, or the wind. It takes suprisingly little wind to blow a bullet out of the group, or grow several bullets out of the group. That is the simple reason all bench rest shooters utilize at least three wind flags at a 100 yards and more often 4 or 5 flags.

[bigted]

moondawg...no i have not had flags as where i shoot there is a large berm rite along side the spot on the far left of the range that i shoot at...not only that i always shoot in the early morning when there is no wind to deal with and there are also not hardly any folks there to deal with either. i will say that i never considered the wind tho for this short of a range. seems a 520 grain boolit would buck the wind better then that at 100 yards...even at the 1100 ish fps.

charlie...i have done a preliminary check on my chamber with my dial calipers with the stem ... the measurement at the flair was 2.100 exactly and my Winchester measured the same as did my ped sharps. not saying this is exactly the best way to measure a chamber but it gives a peek as to length until i get a hammered casting of it to play with and look at.

gunlaker...the lube ring you speak of...is this just ahead of your chamber or at the muzzle?

littlejack...i just loaded 8 loads with 70 grains of goex cartridge and 8 with 64 grains of goex 2f. my different grain-age comes from the desire for the same compression of .360 with the tablet back of .080 thickness and an added .003 tablet paper to isolate the possibility of the heavy wad sticking to the boolit base. the only way i see to cram more powder in the winchester cases is to compress it more then the .360 that somehow i arbitrarily arrived at. i am amazed that there is a 6 grain difference between the cartridge and reg 2f powder...this always makes me wonder why but i guess it derives from the different size grains and the outer polish of the cartridge powder that would allow it to settle thru my drop tube and 'slip' together better then the coarser looking 2f.......i loaded 8 each just for comparison with the thought of using 3 for sighters and 5 for group. im going to town today and if it isnt crowded and i can get my spot then ill try them with the set-out boolit...the oal of these is 2.906 which is a fun length except for the exposed lube ring filled with my lube that threatens to get messy before i can get it from the enclosed tray i use and the chamber....more news when i get to shoot em and see.

[Gunlaker]

Sorry Ted. The lube ring is a ring of lube that comes out with the fired case, attached at the mouth.

If your chamber is long, and you have a grease groove near the case mouth on a loaded round, the lube often forms a little ring attached to the case mouth when you pull it out. The lube seems to take up the empty space at the end of the case.

Chris.

[littlejack]

Hey Ted:
Anxious to hear your results. I believe the shallower seating will solve your problem. I stopped lubing the forward groove. That boolit still
supplies enough lube with 3 grooves.
The 2F would be heavier by volume because of the "fines" that are in it. The Cartridge
powder has had the "fines" screened out.
That is also one reason that the 2F shoots faster. It has the "fines" in it.
I don't know if you charge by weight or volume. My charges are weighed.

Gunlaker:
I get that small ring of lube also.
Jack

[bigted]

well i have to humbly take off my hat fella's...this shallow seating the boolit into the grooves worked splendidly. at first i tried the 2f loads and the blow tube...blowing 5 breaths thru it between shots...same dismal pattern with this load/blowing between shots.

then i tried the cartridge loads...the difference being that i shoved a spit patch between the shots instead of the blow tube. the first shot went high by around three inches. then the magic started to happen...the next shot went into the same area only about 1/8 inch between shots...being conservative with my jubilation i swiped the barrel with the spit patch i had in my jaws and a dry one and shoved in another shell...walla it went in between the first two making a clover like hole in the 100 yard target. these were the three i had planned on to use as sighters ...so i swiped another spit patch thru and a dry one and thumbed in another shell...this one went around 1/2 inch low from the group thus far...now i had 4 shots going into under an inch...never happened before with this rifle... swabbing another spit patch followed with a dry i thumbed in another of these greesy little pups and yanked the trigger...[ i say yanked becouse i fumbled the shot ]...this one going 1.5 inch low from the group so far...swearing gently i swiped another spit patch followed by the dry and thumbed in another making this a 6 shot group...rite into the same grouping with the other shots...sooooo if i can count only 5 out of the 6 then i have a group unlike any this rifle has EVER shot since ive owned it...including smokeless with jacketed loads....now i had three shells left so i popped up another target at the 100 yard mark and let fly just as i done with the previous group...these three went into a nice clover leaf that really made this ol bugger smile n hoot...the other shooters thought id lost my mind id say. what a nice feeling after chasing so long and finally getting what i thought i should be getting.

only puzzle is that these groups stay in the same area that the cleanbore shot goes into...thought they would be going in a different grouping from the clean swiped cold barrel shot...ho hum ...a very nice puzzle for sure

IM A HAPPY CAMPER THIS EVENING!!!

now i need to follow this up with another test with more shots in the group and then if all is well then to follow that with some 2 and 3 hundred shots to see if all holds together.

i need to try the 2f loads again only try the spit patchs this time instead of the blow tube.

thankyou all for your help and here is hoping that this will be repeatable in the future...more news when i can get some more time to devote to this huimmer.......this is me smiling tonite tho.

[littlejack]

That is great to hear Ted. Sounds like you have found that "sweet" spot.
My rifle will shoot that well with the 3-5 breaths through the blow tube. I start with a dry
bore.
I would really like to get a mould made of the 125 that has the first lube groove removed.
It would look like one long driving band up front. That way it would look better than the
grease groove without the grease. The boolit would also have more meat for the rifling to
engrave/grab.
Jack

[Gunlaker]

It sure feels nice when everything comes together doesn't it? :-)

Chris.

[bigted]

littlejack...thanks again for the hint. and i never answered your question od whether i weigh or volume my grains of powder...i weigh all bp as im still trying to take all human out of the equation for the best in accuracy i can get........iam still happy that the group stayed with the first shot too...this will be a great hunting load as well with no worries as to where the first shot is going to go or where the other follow-up shots would be.

gunlaker...yes it it a very nice feeling when it all finally comes together...i think my antics at the range yesterday when i got the second clover-leaf 3-shot group will be a storie for a couple of guys there...lol...well im glad the clown was me this time...HA.

im still anxious to do a hammer cast of the chamber and lead to see exactly where im at length wise...but will prolly wait to do so till its too cold to go out and shoot. if the chamber is on the longish side can i get some 45-90 cases and trim down to fit the bastard size chamber? i have some 45-120 cases left over from another experiment gone wrong so maybe these would work for longer 45-70 cases.

[Don McDowell]

Ted if you're getting good groups and little to no leading in the throat , don't worry about the length, there's other things to concentrate on..

[montana_charlie]

if the chamber is on the longish side can i get some 45-90 cases and trim down to fit the bastard size chamber?
... or you can buy a tool that will stretch those cases.
CM

[Lead pot]

I read a lot were they say they have a chamber deeper then 2.1 or 2.4 fro the .45-70 or the .45-90. I have chamber reamer drawing for every caliber for my Shiloh's. I dont think people understand that the depth of the chamber is from the front of the rim not the back (head stamp) of the rim. a Shiloh .45-2.4 (90) has a depth of 2.336" from the front of the rim and that is what my chamber cast shows also and the rest of the chambers in in the 44, 40 and the 50 are just a little short too.
If a rifle has something longer the extra length comes from a deeper rim recess or excess head space or both. I would bet some of the mass produced rifles might have a problem with poor chamber work or head space.

[montana_charlie]

a Shiloh .45-2.4 (90) has a depth of 2.336" from the front of the rim
So, adding .070", the 'standard' for rim cut depth, your chamber is 2.406".
Not too bad, and not long enough to need stretched cases.

But, what point were you wanting to make?

CM

[Lead pot]

And add another .002 or 3 head space you will have 2.408 or 9 total length from the back of the rim or a little more if the rim recess is cut to .072 deep.

[rbertalotto]

I'm having a heck of a time getting my Winchester 1885 with the Badger barrel to shoot. I bought this rifle and a Pedersoli sharps at the same time. Both in 45-70

The Sharps shoots in the 1.5" area at 100 yds for 5 shots.

The 1885 is double this no matter what I do.

The Sharps can take a 525g boolit seated quite a way out before touching the lands. the 1885 has zero lead so the boolits must be seated deep or it won't even chamber them.

Here is a Cerrosafe cast of the 1885 chamber

http://images57.fotki.com/v81/photos/2/36012/9654765/DSC_2730-vi.jpg

It looks like this chamber might have been cut for breach seating of boolits?

Sharps typical target:
(10 shots with 6X Malcolm scope at 200 yds)

http://images112.fotki.com/v106/photos/2/36012/9730091/0513111156-vi.jpg

1885 typical target:
(5 shots with 6X Malcolm scope at 200 yds)

http://images9.fotki.com/v120/photos/2/36012/9654765/0525111758-vi.jpg

I've tried every conceivable powder, lube, alloy...........The Sharps shoots everything extremely well. The much more expensive BPCR Winchester is extremely frustrating.

My next step is to extend the throat with a proper lead. I'm going to chamber cast the Pedersoli Sharps and have a throating reamer made to match.......

[Gunlaker]

Roy have you tried a tapered bullet? Dan Theodore and company have had excellent results using a zero freebore chamber and a tapered bullet designed to fit the chamber. I'll bet that a bullet much like the one in my post above will shoot quite well when slip fitted so that the bore aligns the bullet perfectly upon chambering.

Chris.

[littlejack]

Robert:
You said, " I've tried every conceivable powder, lube, alloy"
You did not mention trying a different boolit. Maybe you have?
If I were you, I would try the old tried and true 457125 boolit. It has lots and lots of bore
riding section up front to line things up. Seat it to engrave the first driving band in both rifles,
no matter what the depth may be. You may be surprised.
If you do not have a mould, I will send you some in 20-1 alloy.
Jack

[littlejack]

Robert:
I made a hammer cast this afternoon; Thank you very much MC. This was my first expierience with the technique and it came out absolutly perfect.
Anyway Robert, my chamber looks nothing like yours.
The R-P case I used fired, is 2.090. Neck sized is 2.100. Rim thickness is .066.
From the FRONT of the rim, the length of the chamber 2.070. The diameter is .484.
Then there is the angle cut to the freebore, .035 in length.
The freebore, from the front of the angle cut to the beginning of the lands is .140. Freebore
diameter is .463.
Bore diameter is .4515. The groove diameter is .4575.
Jack

[rbertalotto]

Roy have you tried a tapered bullet?

I'm using 457125 and 457132 Lyman Molds.

One is the blunt round nose and the other is the tried and true Postell bullet.

[bigted]

I'm using 457125 and 457132 Lyman Molds.

One is the blunt round nose and the other is the tried and true Postell bullet.

rbertalotto...i have shot literally pounds of the 457125 boolits and also almost the same amount of the 457643 boolits. i also had tried every conceivable combo i could think of. pounds of powder and so many different kinds of primers it made my head swim. i finally got tired of having my a** handed to me with this rifle so i came here for some other ideas...i was reminded of such a simple thing like loading my boolit up against the lands that i nearly ignored the hint till i remembered that my ruger 25-06 requires the same treatment...and also i did ask for some new ideas and it didn't make sense for me to ignore the very folks i asked help from so i experimented with a dummy case with the primer out and re-sized and expanded and loaded a 457125 that had been sized to .459 in my lyman sizer. i kept loading this boolit in a fraction at a time till the action closed and the boolit had very small marks from the rifling on the front driving band.

needless to say...the accuracy took my breath away with 70 grains of cartridge powder with a .080 card over-powder wad with a note book paper of .003 over the heavy wad to keep it from sticking to the base of the boolit...i sparked this with a cci 200 large rifle primer and then when i fired these i swabbed between shots with a spit patch that i keep in my mouth to soak up the venomous spit my jaws seem to build. then i swab the bore with a clean/dry patch and im ready to fire another. this was the combo for mine and as has been reported before here...the boolit hangs out of the case the whole length of the front grease groove. i didn't crimp these either...just barely took the expanded mouth off the case.

might try this my friend as i came to this point nearly a year after loading my first round for this browning bpcr rifle...i assume that your Winchester to be almost the exact rifle....good luck on your search and believe me i do understand the frustration of this search...after the initial loading didnt result in more then 3 inch groups at 100 yds my swearing under my breath became clear to understand from time to time at the range...nearly came to a point of selling it but the dang thing is sooooo pretty that i cant part with it and now that it shoots...heck i dont know what in this world would ever make me want to part with it now.

[montana_charlie]

The freebore, from the front of the angle cut to the beginning of the lands is .140.
There has been mention in this thread of throats being cut off-center.
Now that you have your hammer cast, check that dimension (above) for each land in the barrel.

If any of them start closer to, or further from, the 'angle cut' then you have that problem. If they're even, then you have a straight throat.

As you found out, your chamber is 35 thousandths deeper than your case length.
THAT creates the opportunity to deposit lead in the end of the chamber.
Placing a grease groove (full of lube) in that zone, or stretching the brass, are the 'cures'.

If you were paper patching, longer brass or recutting the throat would be the only options if you were getting paper rings.

CM

[TENRINGS]

HI GUYS!
I also have a 45/70 bpcr and have tried eveything know to man powder,compression,bullets of many types and weights. it still does not shoot best is 4 moa at 100yds. lotsa of buds have tried they are expert shots. its to far out of warranty to expect browning to help i guess..
last resort is a kreiger barrel why krieger badger was bought out and we are just a sideline now.can't expect much.
i'm lost i have a pedersoil target bpcr that will shoot 1moa @100 yds,1 1/2 at 200..
what to do now???

HELP please!!

tenrings

[littlejack]

CM:
I did look at the land marks while I was taking measurments yesterday. All around the circumfrence, they look the same distance from the front of the angle. This pleases me.
Jack

[texasmac]

Hey guys,

I’m not going to provide a formula for an accurate load in a Browning BPCR because there are just too many variables, but allow me to take some exceptions to the comments on chamber alignment and add other facts about the Browning chambers.

First, I like to respectively take exception to Lead Pot’s earlier comments on the .40-65 chamber. Unless the chamber has been recut, there is no 45 degree angle in the factory chamber. The transition step from the chamber to the throat is 12.5 degrees and the leade angle is 1.5 degrees. I do know that, for paper patch bullets, some shooters have reamed the transition step from the 12.5 degrees to around 2 degrees or less. Lead Pot, you may be referring to this rather than the leade angle

Concerning chamber alignment, I devoted a chapter to chamber concentricity in my book on the rifles. While writing the book, to determine the extent of misalignment, casts were made of fourteen rifle chambers, consisting of seven .40-65’s, five .45-70’s, and two .45-90 Creedmoor’s. The rifles covered the three years of manufacturing (1996-1998). Admittedly this was not a large sample at the time, but was quite sufficient to provide both visual and measurable indications of misalignment. The “bottom line” is that all fourteen rifles had some measurable amount of misalignment. Rifles manufactured in 1996 were generally no worse or no better than 1997 or 1998 rifles. I have since made chamber casts of many more Browning BPCRs with similar results.

After further research on the subject and discussing the data with others, I've concluded the misalignment is well within the norm for "production rifles" and does not affect accuracy to a measurable amount. I did come across reports indicating it’s rather common to find worse chamber misalignments in rifles from other well-known and respected rifle manufacturers.

Although the misalignment is slight, the main reason it’s obvious in the .40-65 and .45-90 chambers is because these chambers have freebore. When a good chamber cast is made of a chamber with freebore even very slight misalignment can be easily detected visually. As noted above, the Browning .45-70 chambers also have some “measurable” misalignment, but cannot be visually detected because the chamber does not have freebore. Based on what I’ve found, I’d guess that the vast majority (95% or higher) of Browning BPCR chambers have some slight misalignment. Regardless, the rifles have built a reputation for high accuracy, slight chamber misalignment notwithstanding.

Concerning Browning .40-65 chamber dimensions, the chamber length is typically 2.123” and the throat has an effective freebore length of approximately 0.190” (front of the transition step to the start of the leade). So as Bigted and others have found, one needs to seat the bullet out a good bit.

By the way, those of you interested in making chamber casts may be interested in my article on the subject. It can be found at http://www.texas-mac.com/Case_Lengths_Chamber_Casts_and_Impact_Impression.h tml. While you're at my website, check out the other articles and my book on the Browning BPCRs. For a short time I've discounted the book from $54.95 to $39.95 (includes shipping).

Wayne

[Lead pot]

Wayne.

I looked at enough Borchardt chambers that had the 12 degree this early Browning .40-65 was like a wall like the rest of the chambers I have with the 45.
I just went through my collection of Chamber casts and I'm sorry to say that I cant find it right now. It might not have been shipped back when I got the reamer to to take out the bad spot so I wont argue about it.
But this is what I changed it to. It is now a 4 degree / 1 degree 30 min. compound and it really improved the accuracy in this rifle.

http://i704.photobucket.com/albums/ww43/Kurtalt/40-65browning.jpg

[texasmac]

Lead Pot,

That's what I figured. Your photo of the chamber cast tells the story. You reamed the transition step from the original 12.5 degrees to 4 degrees. The new extended transition step is now taking up most of the original freebore region. If you ever want to shoot paper patch bullets it, that chamber should be real gentle on the patches compared to the original chamber. By the way, nice reaming job and nice cast.

Wayne

[rbertalotto]

the boolit hangs out of the case the whole length of the front grease groove.

Can't do this with the chamber my rifle currently wears. With most alloys, it is near impossible tp push the bullet into the groves more than a couple thousanths.

http://i704.photobucket.com/albums/ww43/Kurtalt/40-65browning.jpg

This throat area looks like it would work very well. But since my Pedersoli shoots so well, I'm going to duplicate it in the BPCR.

[Lead pot]

Wayne there is no free bore in that chamber throat. This throat will shoot the GG as well as the PP.
This chamber will allow you to shoot a short case with out getting the paper or lead rings, they are none existing.
Most of the original rifles had this type of throat till the coming of the jacketed bullet. It is lead bullet friendly.

[texasmac]

Lead Pot,

I assume you mean there is no freebore remaining after you reduced the angle of the transition step by reaming, because the Browning .40-65 BPCR was definitely shipped from the factory with freebore.

Below is an illustration of the chamber I work up for my book on the rifles. By the way, I also have the original Browning Chamber drawings from the factory.

http://i47.photobucket.com/albums/f165/RealTexasMac/Figure4540-6545-90ThroatBore.jpg

F is the freebore length, which is typically 0.100" but can run a little longer.
G is the leade length
Fe is the effective freebore length because the freebore diameter (E) is slightly larger than the groove diameter (J). Fe also includes the length (D) of the transition step.
C is the transition step angle, which I indicated previously is 12.5 degrees. By the way, the illustration is not drawn to scale.

Not only do I have the factory chamber specs to confirm the dimensions, I also made chamber casts of a bunch of rifles to confirm.
And, by the way, for clarity, rifling is shown without a twist.

wayne

[Lead pot]

My reamer took out all of the rough bad section and that cylinder free bore. I dont have any free bore at all in this chamber it's all lead angle. 4 /1.5 degree compound. The 4 degree is .243 plus the 1 degree 30 min. that cleaned out all of the throat that Browning uses.
All of my other rifles except one of the Brownings in a .45-70 have the 5 degree/2.5 degree compound throat and that lead is .128" long.
My .44-100 Rem straight I'm getting ready to build will have a 5 degree/1'-30" compound lead and I might take the barrel off the .45-70 browning BPCR and put the barrel on it if I cant find a high wall receiver when I get the reamer in a few days.
A 12.5 degree will work just fine but it will still form paper ring and smear lead but it's better then a 45.

[littlejack]

CM:
I failed to post that my chamber length is cut approximately .046 longer than my case length. This is
BEFORE the transition angle starts to the freebore. That leaves a full .081 counting the transition angle.
Jack

[bigted]

littlejack...did you really mean your chamber is 46 thousandths longer then your brass? and also your 81 thousandths counting the transition angle? this seems a bunch to me. i will be surprised if my chamber is near this much long...but the hammercast will tell the storie when i get a couple days off to acomplish the cast.

[littlejack]

That is correct Ted.

[montana_charlie]

CM:
I failed to post that my chamber length is cut approximately .046 longer than my case length.
What you did say is that your measurement fron the front of the rim is 2.070, and the rim cut is .066.
Added together that is 2.136 ... or thirty-six thousandths over length.
You would not add the area occupied by the angle which transitions from 'chamber' to 'freebore'. That zone is typically included as part of the freebore length (if there is some freebore). Otherwise it is a transition between the chamber and the leade.
DON'T think of it as part of the chamber because you don't want your case mouth to extend into that tapered 'funnel'.

Whatever the measurement is actually is, there is a current discussion on that subject, here ...
http://castboolits.gunloads.com/showthread.php?t=129239

CM

[littlejack]

CM:
I understand and agree.
The section of the chamber that I am referring to, just ahead of the case mouth, DOES collect
the lube and or lead particles and debris. The chamber cast shows this section as
being NOT smooth like the rest of the chamber.
With the way the rifle shoots, I am leaving a very "well enough alone"
Jack

[montana_charlie]

The chamber cast shows this section as
being NOT smooth like the rest of the chamber.
Is it possible to post a picture of that chamber cast? I would just like to see how it came out.
CM

[August]

I've owned two 45-70 BPCR Brownings. They were so precise in their operation that I could develop sight settings for one rifle and they would be exactly correct for the other. They both shot small groups as far as I could see. I kept the best of the two and sold one. I'm sure the guy who bought it is still shooting a knats eye out at 500 meters with it.

I have had my best success with bore-rider design bullets (money and mathews particularly) of large size. The gun really likes bullets seated way out.

I'm gonna guess your muzzle is screwed up. Get out your magnifying glass and take a close look at the ends of the lands where they spill out onto the muzzle.

There are about a dozen other things that materially affect the accuracy of the loads, but you should be in the ballpark ignoring all of them.

[littlejack]

CM:
I am metally incapable of getting a photo on this site right now. AND, it's not funny.
Jack

[TENRINGS]

If you are refering to me thanks..
I have looked at the muzzle seems ok.but if it is'nt how do i fix it the correct way.
gunsmoths here only do smokeless rifles..

tenrings

[bigted]

If you are refering to me thanks..
I have looked at the muzzle seems ok.but if it is'nt how do i fix it the correct way.
gunsmoths here only do smokeless rifles..

tenrings

a good crown is a good crown. if it keeps the muzzle flat and straight and the rifling is square to the muzzle then you have a good crown...to keep a good crown now is something else. i like the inverted crown that is gradual in the transition from the flat barrel to the muzzle itself...instead of the flat countersunk type that has the sharp edges around the inner countersink. these square corners are a bear for me to clean and keep clean.

if a gunsmith is capable of a good square crown job then he should be able to check/re crown a bpcr gun...same theory.

[TENRINGS]

Hi Ted!
I have the donut style i believe what its called.
Thanks for the answer..

[Yance]

I use the "upset slug" or "hammer cast" method when checking chamber/throat dimensions, but here's Brownell's statement about size when using Cerrosafe;

"Cerrosafe shrinks during the first 30 minutes of cooling and then at the end of an hour, is EXACTLY chamber size. At the end of 200 hours it will have expanded approximately .0025". This factor is well known by all toolmakers and they will take it into consideration when making dies or reamers or gauges from your cast - if you will tell them the cast is of Cerrosafe."

[rbertalotto]

OK, so now we have all kinds of discussions going on about chambers, lead angles, degrees and more. We even have neat drawings!

So, can the collective once again look at this chamber cast from my BPCR and tell me if it looks OK or is something amiss here.

Measurements show zero lead angle after the mouth of the cartridge case. Measurements seem to indicate a very concentric chamber.

Comments more than welcome....

http://images55.fotki.com/v268/photos/2/36012/9654765/DSC_2730-vi.jpg

http://images59.fotki.com/v1593/photos/2/36012/9654765/DSC_2729-vi.jpg

These are photos of the same chamber cast.......

[montana_charlie]

So, can the collective once again look at this chamber cast from my BPCR and tell me if it looks OK or is something amiss here.
I'll say a couple of things about it, but I don't have much background for what I am guessing.

First, I magnified the images as much as Ctrl/Scroll could do it without losing resolution. It would be handier if the photo was a closeup of the case mouth/leade area of the casting.
And, at 290x, it would be nicer if the major feature in the photo was not a big old divot in the casting, right where the leade angle should be (if there was one).

But ... looking beyond those impediments ... I see two possibilities for establishing 'what that barrel was for' when it was chambered.
But, which way I would lean between those two assumptions depends on some dimensions.

What is the diameter (a) right at the case mouth, and what is the diameter at (b) the small end of the transition angle?

CM