Prob w/.40 Snover & Browning BPCR

[pbchunkr]

Hi all -

I finally got everything together to start loading for my "new" Browning .40-65 BPCR.

I cast a dozen test bullets (Lyman Snover, ~8.7 BHN) which came out .4115 dia., 411.5 +/- .5 gr.
Seated a couple unsized (no powder) to top of 1st groove w/an oal of 2.848, and the top band expanded to .413ish.
Pulled the bullets and seating had sized the body to .4085.

Run thru a Lyman .410 sizer except top band, they come out .4095.
I seated, smoked a bullet and chambered it.
No 1st band enlargement, but it shows about .050" rifling marks.

Is this normal?
I understand from texasmac's posts that in these rifles the chamber is 2.125" & freebore is .4115" X (I think) .125".
The band on the bullet is only ~.115 long and this case was only 2.115 long, so shoulda come out .020" short of the rifling.

Whaduyah reckon's the deal?
Should this bullet seat over the top band?

Any insight's appreciated.

regards,

[semtav]

Best way to understand your chamber is to make a chamber cast. then it will become clear to you what is going on. Many of the Browing 40-65's were chambered slightly crooked, resulting in the rifling starting closer to the chamber on one side than the other. If your rifling marks on your bullet are equal completely around the first band yours is true. Mine isn't, but I index everything and it shoots great.

I size mine to .410 minimum . I wound up with my first batch of resized brass at 2.115 also, and I seat my bullet with most or all of the first grease groove showing.
I'll get the exact dimensions this evening when I get home.

Brian

[semtav]

OAL was 2.93, so you are close. The Brownings usually have a .409 + groove, so I would try to stay closer to .410 + on the size.

My rifling starts at .125 on one side and .200 on the other.


Measured from the base, the first rifling marks on mine start at 2.28 from the base

Seat your bullet how ever far out you can for the size you make it depending on what shoots the best.

[pbchunkr]

Hi Brian -

My 2-day old bullet measures .4097 sized.

I partially pulled & reseated to oal of 2.925 (close enough to yours for a trial), smoked & chambered.
It took light thumb pressure on the cartridge to allow the breechblock to close.

Is this true with yours?

Examination showed no shortening of oal and essentially all of the soot to be gone.
And when I wiped & magnified, I couldn't discern any actual engraving.
So I'm now thinking it's just that close a fit. :-)

What sort of indexing takes care of the off-center chamber?

Thanks.

[blindeye]

I have one of the last of those rifles made. Using the Snover bullet also but with minimal case resizing and a .410 expander for Smokeless loads. With less neck tension my very soft 80/1 bullets don't have the body sized down during seating nor the nose distorted. Using that alloy with my mold bullets drop at .410 and are run thru a .410 Lyman die to lube but not size. After passing thru they are still .410 with a slight burnishing. I don't size brass for BP loads. It doesn't sound to me like your bullets are too large but that your expander is too small.

[pbchunkr]

My dieset is Lyman w/.4075 expander, neck I.D. ~.406, best I can measure, so ~3 1/2 thou tension.

Haven't found where I stashed my pure lead yet.
Alloy is rangescrap @ ~8.7 BHN, Lyman 450 lubrisizer/Lyman sizer die.

That expanded-when-seated bullet was unsized.
3 more sized didn't expand - seems odd that <.002 would make the difference, even w/the neck tension.

So far, I've not loaded/shot anything, but I will be using BP (w/a lot more ?? then, no doubt).
Right now, I'm trying to get the bullet/seating/etc.

Been hunting/shooting/reloading for years, but never tried target other than a lot of benchtesting.
BPCR is very daunting to a newbie, after reading about all the sorcery involved. :-)
May be overthinking a little.

[kokomokid]

i start with a new boolit in my 40/65 by putting a dowle rod down in closed breach with firing pin back and get a precise mark. Next lightly seat a sized boolit with a pencil and eraser in the chamber and get another precise mark and you have a good OAL starting place. I like to start about .004 long with the snover.

[pbchunkr]

Using that method, semtav's 2.930" looks right.

I think I'll go with that to start - it's about time to load up and make some smoke, puttin' a few downrange, soon as the weather permits.
The fun begins. :-)

[semtav]

If memory serves my, the freebore is actually tapered a little bit, cuase i remember scratching my head on about the same thing when I started, finally thinking tapered freebore which was verified by Wayne.


find posts by TexasMac on BPCR.net forum



Edit postReport this postReply with quoteRe:
by semtav » Fri Oct 02, 2009 11:50 am

TexasMac wrote:
Jim, all the Browning .40-65 chambers I've made casts of had just at 0.411" freebore diameters and averaged around 0.409" groove dia., so I'm not surprised you're getting good results with a .411 bullet. Generally I find that the least the bullet has to bump up to match the throat or bore dimensions the more accurate the bullet will be.

Wayne


Wayne

did you ever cast the chamber of the 40-65 you recently sold me??

I can get a .409 bullet to stick out farther than a .410. (.230 vs .130) If I try to leave the .410 bullet out as far as the .409, the first land of the bullet shows signs of dragging and takes some pressure to fully seat.the .409 bullet (Saeco 410 gr) is only limited by the nose hitting the riflings, but .410 Snover is being limited by the dia of the freebore I believe.

My cases are all 2.125 length

I am not set up to cast the bore yet, but hope to some day soon.
Briansemtav

Posts: 103
Joined: Sun Sep 27, 2009 2:07 pm
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Report this postReply with quoteRe: One reason for a chamber cast
by TexasMac » Fri Oct 02, 2009 3:55 pm

Hi Brian,

No, I didn't cast the chamber or bore of your rifle. Looking at the chamber cast data I have from other Browning .40-65 rifles, the freebore diameter averaged 0.411" but ranged from 0.4105" to 0.4115". If your rifle's dimensions are at the lower end of the range or slightly smaller, I'm not suprised a 0.410" dia. or slighly larger bullet meets some resistance, especially if the bore is fouled from a previous shot. Because the Browning 40-65 freebore dia. is larger than the bore dia. the freebore consists of two sections, a constant diameter section approximately 0.100" long and a tapered or cone-shaped section approximately 0.050" to 0.070" long before reaching the start of the leade. From you description it sounds like your 0.410" dia. bullet is meeting resistance when it comes into contact with the tapered section, which does not surprise me.

[pbchunkr]

Thanks Brian.

No luck getting to BPCR.net - must have server probs or sumpin'.

[semtav]

www.bpcr.net

comes right up for me

[Doc Highwall]

pbchunkr, the .0035" tension on your bullet is too much press fit for your .4097" bullet with your 8.7 bhn. Your expander plug should only be about .001" to .002" smaller then your bullet size and with your soft alloy I would try a expander .0005" to .001" smaller as you can always polish it down with emery paper.

[pbchunkr]

Thanks for the info, Doc.
A new expander is no problem.
It has occurred to me that I'm dealing with newly formed cases here.
Reckon I really oughta fireform 'em, then see whether they need to be sized at all.

As I said - BPCR is terra incognito for me. :-)

BTW semtav -
BPCR's loading ok now. ;-)

[pbchunkr]

For general consideration:

Wonder if stickyback aluminum tape, a la Beagling, would work even temporarily to increase the expansion?

Anyone have some & willing to try?

[Dale53]

I shot BPCR Silhouette for fifteen years. My favored rifle for this sport was the Browning BPCR in 40/65.

I have access to a 500 yard range only 45 minutes away. I temporarily mounted a 20 power scope on mine for test purposes off a bench.

I shot 30/1 lead/tin bullets sized to .410" and seated out to touch the rifling.

My original dies left too much neck tension and they downsized my carefully cast and sized bullets not allowing me to obtain optimum results. After extensive tests, my choice of expander is the same size as the bullet or not more than .001" smaller. Brass contracts after sizing - if the expander is bullet size there will be about .001" neck tension. I noticed NO difference between .001"-.002" neck tension. However, any more neck tension and the bullet was sized by the case.

The Lee floating expander die allows anyone who knows how to operate a lathe to easily make an expander stem. I used the Lyman "M" die for a model with MY dimensions. The Lee expander has no threads so it is an easy modification.

Spence Wolf's book (Loading for the 1873 Trapdoor Springfield) has drawings of exactly how to do this (with the exception of the Lyman "M" die expander nose).

FWIW
Dale53

[kokomokid]

My best shooters are pushed thru a .410 sizer ( drops .4103) and use a .410 Lee expander. As Dale says springback gives a great neck tension. Look at cheap Lee expanders at Track Wolf and you can get an idea for fire formed cases. My OAL for .410 snover is 2.980 but I have a custom cut chamber.

[Doc Highwall]

Dale53, what did you use for a scope and scope bases for your Browning BPCR.

[pbchunkr]

Alrighty then - found expander plug, compression plug, veggie wads on TotW, all of which I'll no doubt end up needing.

Now I mostly need calm, dry weather to do some shootin'! :-)

[Dale53]

I mounted my 20 power Lyman All American (modern scope) with the scope blocks made for the Browning BPCR. That set up is not allowed for BPCR Silhouette but a Malcomb type scope is now allowed (they now have a scope class). After I had vision problems, I installed a Parsons Malcomb style scope on mine (it is necessary to have the rifle drilled and tapped for this). After going to all of that hassle, I lost most of the vision in my right eye and can no longer shoot rifle.

Of necessity, I am now limited to handguns (which I shoot avidly)... I can use my "off eye" for handgunning.

Dale53

[Doc Highwall]

Dale53, you could always learn to shoot left handed like I do. I know all about shooting with only one eye. I see only with my left eye and shoot rifle and shotgun left handed but I shoot handgun and bow right handed. If you get yourself a good 22lr and practice with it I am sure you will do better then you might give yourself credit for. Don't give up!

[semtav]

The Lee floating expander die allows anyone who knows how to operate a lathe to easily make an expander stem. I used the Lyman "M" die for a model with MY dimensions. The Lee expander has no threads so it is an easy modification.

FWIW
Dale53

Thanks for the idea Dale
I made a .326 expander for my Siamese mauser this morning.
I've never done threads, so just never tried one for the M dies.
this way is slick.
Brian