Mosin Nagant 91/30 Adventures

[treadhead1952]

Hi All,

I have been reading up on all that I can find on the 7.62 X 54 R so that I can load up some cast boolits when I actually accumulate enough brass to do so. My nice shiny Ishevsk made 1933 91/30 arsenal rebuild with J@#$#%#$%d bullets seems to do pretty well but I am sure that with some judicious load development it can do much better.

http://img.photobucket.com/albums/v349/treadhead1952/EmT630004.jpg

Following Dutch4122's advice since he seems to be pretty much on top of these things, I have been measuring the inside case necks of my fired Sellier & Bellot rounds. To my amazement they are all coming out at .310". I have a Lee mold that I use for my .303 British SMLE that I was thinking I would use for my Mosin Nagant, but that it would seem is now not going to be a happening thing due to the size differences, .313.5" as cast to what should be .309" using Dutch4122's "subtract .001" from the fired case inside neck diameter" formula. The bore after cleaning out all the cosmoline on my rifle is nice and bright with sharp edges. It has not been rebored at the muzzle. I will be slugging the bore to see what I can see from that, but I was wondering, have any of you more experienced cast Boolit shooters/loaders run across a Mosin Nagant with this tight of a chamber neck?

[rhbrink]

I don't mean any disrespect, but are you measuring that right? Every one that I have had my grubby paws on measured more like .316 to .318. Just asking?

Richard
Missourians for Mosins

[treadhead1952]

Hi Richard,

Being a relative newby to Mosin Nagants and here, that is the reason for my post. I have read a bunch of 7.62 X 54R threads and they all seem to be on the size margin that you pointed out. I checked out all 20 of the fired cases that I have managed to run through my 91/30 and they all look just like this.

http://img.photobucket.com/albums/v349/treadhead1952/EmMosinNagant_030.jpg

I am holding my thumb on the adjustment knob to keep tension on there as the photo is taken and this is the reading that I get for all 20 cases. Closed, my Dial Indicator is right on zero so it isn't a case of mis-adjustment. Checking my .303 British fired cases inside case mouths, also fired on the same day in my SMLE, I get .313" as always. I am just a bit baffled by this size difference. The rifle fired just fine, no excessive recoil, no hard opening bolt handle, nothing to indicate anything is amiss.

[Larry Gibson]

You'll find on many MNs that there is no step or very little if any in the chambers at the case mouth. Most often there is just a taper from the outside edge of the chamber mouth to the leade(where the rifling begins. On many of these the groove diameter is almost as large as the chamber neck diameter. This situation does not provide for as good a "fit" of cast bullet to throat/bore that we would like.

A chamber cast will quickly tell you if the chamber of your rifle is as such. From your measurements and description it probably is. With such a chamber the ".001 under inside case neck diameter" doesn't work so well. If your MN chamber is such you can, perhaps, turn the case necks thinner to allow a larger diameter bullet. You can also cast softer bullets and allow for obturation of the bullet to provide the "fit" to the bore. Try AC'd WWs + 2% tin or with 30% lead added for an alloy.

I've shot numerous such MNs with .312 sized C312-185-2Rs. The last part of chambering is a crush fit. Yes some will decry that pressures are raised or other such but in truth they are not raised with cast bullets. This is especially the when the GC is not seated below the case neck and the softer alloy is used. I have measured the pressure (Oehler M43) of loads with the bullets sized .312 and .310 in a MN and found no discernable difference in peak preassure or the time/pressure curve. The soft alloyed bullets are swaged down when chambered and don't offer any more resistance as the are pushed forward into the bore on firing. I have fired hundreds of such loads without problem in my own M91/30 Ishevsk with just such a chamber. Velocity runs around 1820 fps out of my M91/30.

The side benifit to such is that no case sizing is needed. I use the lee universal expander to slightly flair the case mouth is all and seat another .312 sied C312-185-2R in the cleaned, deprimed/reprimed and powder charged case. My C312-185-2Rs when cast of WW+2% tin+ 30% lead weight 189/190 gr fully dressed and shoot very well over 24 gr AA5744 with no filler.

Larry Gibson

[6.5 mike]

rhbrink, just to show how odd they can be, Ishevsk 91/30-1943 0.302/0.3105, remington m/91-1917 0.3015/0.3095. I have slugged others that were more in line with what you're seeing. :popcorn:

[walltube]

First thing to do, is relax. You're dealing with a firearm subjected Soviet era QC.

In my exp., Mr. Gibson's response is spot on about softer alloy Pb boolits. They will, within reason, mash right down to fit. There is a M44 now hiding under a bed sporting a .305 bore and .3137 groove depth. NOE's 316299 cast of air cooled WW, sized to .315 with 16gr. 2400 has been a pleasant and satisfying combo. And yes, there is a slight resistance felt when chambering such a round.

I will suggest you put your caliper thingy a bit deeper into the case neck. Given varying brass wall thicknesses and chamber tolerances (?) you may see a difference in indicated numbers.

Good luck with your M-N,
Harold

[treadhead1952]

Hi Guys,

Thanks for the advice and suggestions.

Harold, I did stuff the blades of the caliper all the way down into the neck and got this for a measurement.

http://img.photobucket.com/albums/v349/treadhead1952/EmMosinNagant_031.jpg

Rotating the cartridge case a bit more it even went down to this.

http://img.photobucket.com/albums/v349/treadhead1952/EmMosinNagant_032.jpg

So it would seem that Larry is right about the taper in the case mouth area. That leads me to wonder more about the chamber dimensions as well as the rifled tube itself. So slugging and a chamber cast would seem to be in order. That is, if I really want to find out about how this thing is shaped. If, as it would seem by the measurements, my chamber is tapered as well as out of round, I can't help but wonder if perhaps having it's chamber in the case mouth area cleaned up so that it is round and a straight cylinder from the end of the case taper to the end of the case itself, be a good idea, especially if I want to run cast lead boolits. Doing so would allow me to run boolits that would better match rifling dimensions rather than dealing with a crush fit that obturation would involve.

Decisions, decisions, decisions........:cbpour:

[rhbrink]

Just do what walltube says "relax" go shoot it some bet that brass will round it self out after a few rounds. I had one that did something like that maybe some cosmoline in the chamber? The first few times that I fired it the case mouth was just like yours tighter than the rest of the neck, I was thinking my God what do I have here a total Commy srewup they can't do anything right. But after a few rounds things started working better and ended up with a pretty good shooting Mosin. Sometimes it takes a little work but every one that I've dealt with maybe 5 or 6 have ended up shooting way better than expected. As long as there is a reasonably good bore they can be made to shoot.

Richard

[treadhead1952]

Hi Richard,

I guess I will just have to shoot it some more, have to accumulate some brass to reload anyway. As I do so I will keep an eye on things to see if maybe they iron out a bit. I did notice that of the 20 cases fired, 2 of them seemed to have the primers blow out as they look like little dark spots instead of like the other 18. I was shooting on a 100+ degree day and shooting out here in Nevada does sometimes do strange stuff to ammo. The rest of the primers all look like a little flow back around the tip of the firing pin and cratered just a tad.

http://img.photobucket.com/albums/v349/treadhead1952/EmMosinNagant_033.jpg

These were Sellier & Bellot 180 grain Softpoint Hunting Rounds to start with. I have another box of them that I will be shooting off sometime next week and hopefully purchase another box come the following Friday. I will be keeping my eyes open for some of the Golden Bear, Privi Partizan, Winchester and Remington rounds if I can spot any locally. As I get the time I will avail myself of some of the online dealers to add to the brass collection.

I am thinking that I will hunt down one of the Lyman .314" .303/7.7 MM moulds, it would seem to be a better fit for this one and the 200 grain weight will probably do fine in this 1 in 10" twist rate barrel. I would also like to see how my SMLE does with the extra 15 grains and .002" of bullet. Other than the size and weights, the two bullets from Lee and Lyman are the same round nose profile with a gas check. The other options that I have are 155 and 160 grain bullets intended for the 7.62 X 39mm rounds. Both of them are sharp pointy types. Decisions, decisions. ;)

[walltube]

treadhead1952,

There Ya go, Larry Gibson is, as usual, not "seemingly" correct, he is correct. A Cast Boolit Emeritus will not, IME, lead you astray.

I must ask you, have you given much effort cleaning the chamber and throat as the rest of the "inner" tube? The neck and area just beyond the case mouth, when a cartridge is fired, is often subjected to a great amount of carbon and metallic fouling. This can and will register an incorrect caliper reading. It is the nature of the beast with mil-surp ammo.

Please keep in mind: your M-N is not a virgin bride. :lol:

Because you are asking, I'd say Privi is the best brass for the dollar spent. On the other hand, if your budget allows, Lapua.

Buy a NOE mould.

Y.T. and have a good 4th. wk. end,
Harold

[rhbrink]

Brass seems to be hard to come by right now but certainly keep looking. I would do as walltube says clean the $hit of the chamber and throat area. It would help a great deal to make a chamber cast just to see just what you are dealing with before you by a mold. These things can be all over the place as to dimensions and wear, see what you have and then buy a mold to fit maybe a standard mold would work but wouldn't bet on it. The only bad thing about the group buys is that sometimes it takes many months to get your mold but every one that I have received has been well worth the wait. I do have some saeco 315 and 305 boolits that I could lube up and send you to try if you would like I have had pretty good luck with both of these boolits in the Mosins if the throat isn't too big.

Richard
Missourians for Mosins

[3006guns]

I ran into a similar situation when measuring case necks recently. They appeared to be smaller, or right at groove diameter.....until I realized something.

Look at the blades of your dial calipers. They're square, not perfect knife edges. Now imagine measuring the inside of a circle with those blades and you'll realize that the blades don't get all the way to the inside edge of the circle, hence they read less by a few thousanths. Plus, you have to hold them "just right".

I got a set of small hole guages off Ebay. These have a split, ball shaped end which is enlarged by drawing in a wedge as you turn the handle. You keep enlarging the ball until you have an easy, sliding fit in the case neck then measure it with an ordinary micrometer or dial caliper. You'll be suprised as you suddenly "aquire" two or three thousandths!

[Andy_P]

....Yes some will decry that pressures are raised or other such but in truth they are not raised with cast bullets.
Larry Gibson

That's a provocative piece of info that I never heard before. It seems plausible, but can it enter unchallenged into the book of cast boolits truths? I have nothing to contribute to the contrary.

[mroliver77]

I second the clean the heck out of the chamber opinion!

Larry advises a chamber cast. I do what I call an impression cast of the neck/throat area. This will give you the info you need.

First clean the gun well. Lightly oil the barrel and chamber!! I cut the case neck back .100" or so then fill the case with a steel rod or piece of bolt or whatever leaving a bit of room in the cut off neck. I use a piece of lead wire or a heavy pure led boolit rolled between two steel plates to reduce the diameter and lengthen it. I either put this in the case mouth and load it into camber or load the case and drop wire down the barrel. I have a selection of steel rods from the hardware store that I pick the one that fits the bore the closest. I wrap some black tape every few inches to protect the bore and then drop it down the barrel with the gun standing up. Using a hand sledge (2 lb) or 20 oz framing hammer I give a couple good whacks on the rod to upset the lead and flow it into the neck throat area. You can tell when it is enough as the rod kinda rings and bounces back at you. You do not want to overdo it! I then open the bolt slowly and very lightly tap the rod to help push the slug out. You have a perfect impression of your neck area that does not change and can be kept for future reference.

Here is an early one I did of a Mauser. It is kinda beat up from rolling around the bench for years. I buggered the mouth to help hold the slug in the case but later found it not necessary. You can see and measure the exact chamber length and know for sure how long to trim your cases. You also know the exact I.D. of the chamber neck and from this figure the largest safe o.d. of the loaded case neck. The taper talked about can readily be measured. The throat design is then known. The one Larry describes is very common in 30-30 and makes me wonder what the designers were thinkin! Here is the best pic I could get of the slug.

http://castboolits.gunloads.com/imagehosting/2074e10d6f50b9ae.jpg

Here is pic of the 30-30 Marlin micro groove with the chamber going from the case neck size down to bore size like a steep funnel.

http://castboolits.gunloads.com/imagehosting/2074e10d67701cf8.jpg

[treadhead1952]

Thanks for the replies everyone.

As I am new to the Mosin/Nagant 91/30 series and cast boolit feeding to them, all the help I can get is appreciated. I have cleaned it twice more following the guidelines on the 7.62X54R.net site and I haven't seen any traces of cosmoline or old crud coming out of the bore or chamber any more, the patches are as white coming out as when they go in now. Using lights, patches and even a piece of light fiber to put the light specifically in certain areas of the chamber to look for any old crud that may be burned onto the surface, I can't spot anything other than nice shiny metal. And that is in a dry un-oiled bore that has been repeatedly wiped out with clean dry patches.

I hope to get out sometime this week to shoot it again and see what results I get with the fired cases. Especially since I now know to shove those jaw tips down in there to get the best measurements possible. 30-06, I will look around to see if I can locate some hole gauges like you describe, I have some but they only go down to about a half inch for the smallest size. Perhaps the Harbor Freight Technical Measuring set they have has some that would be usable.

Richard, your offer is generous to a fault and I do thank you for it. I will be getting more brass and purchasing that Lyman mould to add to my collection as soon as possible. Shoot, I don't even have a set of reloading dies for it yet! But before I start stuffing some cast lead boolits down the bore I have more homework to do with it to satisfy my own curiousity.

MR, thank you for your suggestion, but I am a bit more cautious than using a steel rod inside the bore at the moment, padded with black tape and all. I would use either some Cerrosafe to make one or take it to the boys over at Rifle Dynamics and let them make a chamber cast for me. If Rifle Dynamics does the job, they told me that they will do a thorough cleaning job before they make the cast so that is also a plus there. As I am planning on buying a couple more Mosin/Nagant type rifles and carbines once I get my C&R FFL all this information and work will go to good use on more than just the one firearm.

Again thanks for everyone taking the time to offer up suggestions and advice. After reading through a lot of the threads, I knew that I could get some help from the membership here.

[emrah]

I'm having a hard time understanding how measuring the inner case mouth can give an accurate indication bore/groove diameter. Or what size boolit you need. I've tried this with my .30-30 and my Mosins and they're nowhere close.

My Mosin slugs .3135-.314. I tried shooting .312-.313 boolits through it and it leaded like crazy after just a few rounds. I definitely need .315.

But back to measuring the inner case neck. How does this work and why?

Emrah

[treadhead1952]

Hi Emrah,

It was something that I picked up from a thread in here. The inner diameter of a fired case is supposed to be a starting point to give you the cast boolit diameter that you can safely load in that particular rifle allowing for the thickness of the brass and the chamber diameter. I was hoping that the gentleman who came up with it would jump in here but so far no appearances. He apparently loads for a number of Mosin/Nagant rifles and carbines as well as other mil-surp firearms and does quite well with cast boolits. Larry Gipson pointed out a few things that sort of correlates to what I read. My problem was with not knowing how to use the caliper to its' best advantage in measuring the inside case neck, didn't go down in there far enough.

From my experience with my .45 Colt revolver with it's .451" bore, the .452" 225 grain round nose bullets I load for it work most excellently. With my SMLE in .303 British the .313" bullets as cast from my Lee Mould, tumble lubed do great in it's .312" bore.

[JIMinPHX]

Much good advice has already been given. I would like to add a question or two & a few comments.

First, what are you learning by measuring the inside of the case neck? After a case expands when fired, I would expect that it shrinks back up a little. I also would not be surprised if it gets knocked a little out of round when being ejected.

Your measurement should probably be taken with a grain of salt for a couple of reasons. First & foremost, I don't trust those Chinese dial calipers to be accurate to the last .001" Second, there is a slight measuring error when using caliper jaws that have a small flat across them when measuring the ID of a round surface. The error generated by the flats is slight, but it is there. You can calculate the "chord dimension" if you would like to make a correction for the flats.

If you would like to get an idea of how accurate those calipers are, then measure the shank of a brand new, name brand drill bit. It should come up right at .3125", which is real close to the dimension that you are measuring. If that measurement is off, then your case neck measurement is probably off by a similar amount. It might also be handy to see if you can jam the 5/16" shank into the case neck. If you can, then the average diameter is at least .3125".

After seeing your spent primers, I would certainly inspect your firing pin. The nose of it should be a smooth dome & it should fit in the hole in the bolt head with only a few thousandths of clearance. Judging by what I see, that's probably not the case. That action is as solid as a rock. I don't expect that the action will see any real damage from primer leakage, but you might get some genuinely unpleasant hot gas/shrapnel splatter back in your face if that situation is not corrected.

I would also like to add that Russian Cosmoline that has been sitting in Siberia for 50+ years can be some unbelievably tough stuff. I fired an old Russian Milsurp for more than a year, thinking that it had shallow rifling. After MANY repeated cleanings, I found that the groove diameter was about .005" larger than I had originally thought. I know that you say that your bore is shiny, & you may be one of the lucky ones that actually got a good bore, but please take another look & go in with the mind set that a thin, rock hard, layer of Cosmoline can be a hard thing to recognize sometimes.

[6.5 mike]

After looking back at your fired cases, JiminPHX has given you some very good advice, you primer hits are "to square" at the bottom, this caused the pericing on a couple. The pin hit should have more of a rounded look, if you have some fired cases from another gun you can compare them to see the differance.
Andy P, Larry is correct on this. A good example is my 7 m/m tcu bbl, starting load IMR 4198, 140 gr j bullet, cci primer used to sight gun in. Same load & primer, Lee 130 gr pp'ed shoots one inch high with no scope change at the some range, only thing I figure is the differance in "drag". This is'nt the only one I've had do this. The differance between naked & dressed also shows at POI change, example, 03A3 lee 200 gr lubed & checked, same boolit pp'ed, same powder charge, primer, & case.

[emrah]

A note to Mosin shooters about the primer dent issue: As you may or may not know, the depth of the firing pin is adjustable on the Mosin bolt. Look at the back of the cocking piece/safety knob. There is a little flat-head screwdriver slot. Turning this in/out adjusts how far the firing pin protrudes. Yours may be adjusted too far out.

The knob usually has scribe marks in line with the screw head slot. Yours may be 180 degrees or even a full turn too far.

Most Mosins come with "kits" that have a firing pin depth gauge. I don't have one and don't know how to use it anyway, but my primers always look fine so I'm content.

Anyway, just something to think about.

Emrah

[leadman]

That S&B ammo seems to be loaded to the top end of pressures also. I had some and it chronographed faster than my 30-06 ammo with the same weight bullet.

I have other American factory ammo pierce primers here in Phoenix when temps are over 100 degrees. Almost common with Remington ammo.

If the OP has a chrony it would be interesting to see the velocity. Not saying this is his problem, but will be interesting to see what another brand or ammo fired during cooler temps does.

[treadhead1952]

Thanks for some more suggestions everyone. I will look at the firing pin tip again, when I disassembled the bolt to clean it I did check the firing pin tip protrusion with the tool provided in the cleaning kit and it did fall between the short and long gauges on the side, which is sort of what I thought it was supposed to do.

Shooting here in Nevada can be interesting, especially in the summer months where temperatures can reach 120+. With hot hand loads or warm factory loads, this can lead to some interesting things happening. One of the reasons that I was not overly concerned about the primers on the first 20 cases. I have seen similar results on .357 Magnum, .308 Rifle and .338 Winchester cases in the summer months. I always wear shooting glasses and hearing protection when shooting because of this and other safety reasons.

Reading Dutch4122's posts about checking the fired cases case mouth for a clue as to what sized cast boolits to try out first time around, is where I came up with the idea and I am not so sure that it is wrong or right. Again, it may have something to do with where I live or even issues that are not related at all. I will continue to look about and shoot the rifle more as time permits and eventually it will get worked out. I will continue to clean my rifle each time that I shoot it, I do this anyway and eventually even if I am missing something, it will come completely clean.

[res45]

S & B ammo at least the few caliber I have shot seem to be one the warm side,they also make the Win. brand of 54r ammo as well. S & B is also the same company that made the surplus steel case ammo that comes in the blue/green 20 rd. boxes many Mosin shooters are acquainted with. The 54r being a European cartridge is loaded to C.I.P. standards not SAMMI with a Max. pressure of 57K PSI

One thing I have noticed is that the 54r boxer primed S & B/Win. ammo or Win. primed brass primers seem to be a bit thinner than American made primers I'm accustom to,I have a few that the decapping pin actually punch through while resizing.

The first thing I did with my Mosin M44 was clean the chamber and bore well and set the firing pin protrusion http://www.surplusrifle.com/reviews/wolffmosinspring/index.asp

Before I started reload and casting for the rifle I shot Bulgarian 1950 surplus LB and HB ammo it always cratered the primers and pierces a few so I broke downs about 100 rds. and dropped the powder charge down one full grain and evened out the charges and reseated the bullets. I never had any issue with any cratered or pierced primers with any of that reworked ammo afterward it even shot much more accurately.

Before
http://i76.photobucket.com/albums/j1/rhsikes/res45/Ammo007.jpg
After
http://i76.photobucket.com/albums/j1/rhsikes/res45/Ammo008-1.jpg

One the subject of the cast bullets that my rifle will chamber without altering the case neck thickness on the Prvi and Win. brass I have,the fattest it will chamber is .314" dia. and that's a snug fit. I shoot the Lee .312 dia. TL gas check bullet cast from WW alloy it drops from the mold at .313 and I apply the gas check with the Lee .314 sizer. My bore slugs at .312 across the grooves and I shoot a slew of these bullets with 16.0 grs. of 2400 or 13.0 grs. of Red Dot and have never had any leading issues.

[walltube]

All Ya'll,

What JiminPHX says about Soviet, half century or more, old cosmoline, InMyEx, is very much so. And this, as well, may apply to other 20th Century 'new'-to-the market mil-surp bolt rifles.

My go-to proceedure for removal of metallic bore fouling has traditionally been Outers electro-chemical system. Removing layers of cupro, then scrubbing away burnt powder residue in turn always seemed to be the real deal. I say "seemed", because that is what it was; seemingly. Worked well enough for other guns 1st. try, not so well with those mil-surps of unknown history with cosmoline coated bores.



I came to an awakening of sorts when a gentleman at the range introduced me to the era of Foaming Bore Cleaners. Using this stuff is what truly revealed the M44 .305x3137 bore\groove measurements. There was some of the dark Cu blue-green present with 1st. patch thru, but, my goodness the black sludge was something to behold. Ancient, hardened cosmoline met its match. Two successive applications and there it was, some surprisingly bright, sharp rifeling. Does not disolve lead, but will loosen other deposits making lead removal easy. Boolits respond well to clean 'inner' tubes.

About those finely crafted Sino battery powered calipers and micrometers: weak batteries will render unreliable readings. I keep on hand several packages of batteries, and check calibration often. Good quality feeler gauges have kept Chow-Mien, Inc. tools reasonably honest. Well, at my bench it's so... :)

Support our CB vendors and tool makers,
Harold

[nicholst55]

A note to Mosin shooters about the primer dent issue: As you may or may not know, the depth of the firing pin is adjustable on the Mosin bolt. Look at the back of the cocking piece/safety knob. There is a little flat-head screwdriver slot. Turning this in/out adjusts how far the firing pin protrudes. Yours may be adjusted too far out.

The knob usually has scribe marks in line with the screw head slot. Yours may be 180 degrees or even a full turn too far.

Most Mosins come with "kits" that have a firing pin depth gauge. I don't have one and don't know how to use it anyway, but my primers always look fine so I'm content.

Anyway, just something to think about.

Emrah

Here's a link to Mosin bolt disassembly/reassembly, to include how to adjust firing pin protrusion. Figure that if an illiterate peasant conscript could do it, y'all can too! It sure ain't rocket science!

Bolt Disassy/Reassy (http://www.surplusrifle.com/finnishmosin/boltdisassembly/index.asp)

[HARRYMPOPE]

My experience with 312 bullets and chambers are the same as Larry's.i have five Russian 91-30's with good bores right now and all do fine with that loading procedure and i haven had to resort to any bullet fatter than .313 to get accuracy at 2 MOA or under with irons.I havea mold that is .310 but has a .303 nose and it also shoots well.

HMP

[Pollomacho]

These were Sellier & Bellot 180 grain Softpoint Hunting Rounds to start with. I have another box of them that I will be shooting off sometime next week and hopefully purchase another box come the following Friday. I will be keeping my eyes open for some of the Golden Bear, Privi Partizan, Winchester and Remington rounds if I can spot any locally. As I get the time I will avail myself of some of the online dealers to add to the brass collection.


I've had pretty good luck with the factory loads on those S&B 180 gr SPs, but the brass seems to only take a single reload before the rim wears a little thin. This is not with hot loads either, my work-ups seem to be giving me trouble too. I've had better luck with the winchesters, pps and remingtons, but have yet to reload any golden bears for comparison yet.

[Dutch4122]

Treadhead-

Sorry that I have not responded to your thread sooner. My computer totally gave up the ghost several weeks ago; and I had to have a new one built from the ground up. I'm just getting back to the forum and trying to get caught up with the goings on around here.

When measuring the inside of the case necks I found the same issue as you did with the variations between the end of the caseneck and farther down inside. I have always inserted the calipers as far down the caseneck as I could for an accurate & consistant measurement to work with. With 5 Mosins out of 6 so far checked I have found that those 5 will safely chamber a .317" boolit.

I was taught this method by 45 2.1 several years ago. Using the largest boolit the rifle can chamber safely is meant to help start the slug off straight towards the rifling. When this method is used with a bore riding slug that engraves the nose on chambering there is a good chance you'll achieve tighter groups with the Mosin.

One thing about these rifles I have found is that trial & error is usually worth the effort. Try every boolit design you can get your hands on; as well as every different loading method out there.

[treadhead1952]

Hi Matt,

I was beginning to get a bit worried that maybe you had gone on to bigger and better things or perhaps I was havin' a flashback from my days in the early 70's :wink:

I have a feeling that the tapering in the case necks has to do with the brass just springing back down after having been fired after doing a lot more reading from a bunch of sources. Neck resizing brings it back to a more uniform dimension top to bottom of the area and when you add your own reverse taper to enable seating a cast boolit with an expanding ball you have just turned it all upside down. Right now the only bullet that I have to use for this project is the Lee 185 grain .312" round nose gas check designed mold. As observed earlier, it does drop a .313" diameter boolit from the mold. Seating a .30 caliber Hornady gas check using the .314" Lee sizing set is where I will start my experimentation.

Between powder variations, seating depth adjustments, brass case tricks and trimmings and various poossible fillers to utilize from dacron fluff to cream of wheat to shotgun plastic buffering I have a whole host of possibilities to experiment with. And as you say, somewhere in all of those combinations will be one or two that will be preferred by my particular Mosin-Nagant 91/30. And yes, it is all worth it when you step up to the firing line and can produce a nice little grouping with an older mil-surp firearm that rivals what the modern factory rifles sometimes have a hard time getting close to without similar ministrations.

walltube, I have to agree, checking your measuring devices to make sure that they are giving you an honest reading is a good idea as well as any other requirements like fresh batteries and such. Even European and American made instruments require a check once in a while to verify what you are actually looking at. Just like I have a check weight set for my reloading scale, I use feeler gauges to check the accuracy of my dial calipers.