Bullet Alloys for Military Rifles

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  • Last Post 10 October 2010
Tinkerer posted this 12 September 2010

I've been trying to get the best accuracy from a Krag rifle that I've just rebarrelled.  I'm currently casting Lyman 311284 bullets from wheel weights which are dropping out at about .3105.  The barrel slugs at .300/.308 and I've tried .309 and .311 sizing.  I've seen the best group width using 16 gr of 2400.  The group height is what I'm working on.  Today the 10 round group was about 3” wide and 10” tall at 200 yds.  The loads chronograph at about 1550.  When I increase muzzle velocity the group opens up and I'm thinking the wheel weight may be the cause.  Can anyone tell me what alloy would allow me to increase muzzle velocity without losing accuracy.  I want to flatten the trajectory....Thanks....:cool:

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longround posted this 12 September 2010

Tinkerer Go to military match results on this site. Pull up Dakota Benchrest Shooters for an example. We have not seen a Krag out there for a long time but look at the alloys in the tech data columns.You will see what the high score shooters use.You can do the same with any club listed, You use 2400..good choice. Good luck. TK

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tturner53 posted this 13 September 2010

A lot of great groups have been shot with straight ww, especially in that velocity range. I would suspect some other cause of the vertical stringing. That said, there's a formula for figuring bhn needed based on pressure in cup. I don't recall it right now, but someone will. The pressure is the real issue, although that relates to speed. For generic purposes, you could heat treat your ww bullets and push them much harder, probably more like 2,000 fps., if they are a good fit with good lube.

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redball 2 posted this 13 September 2010

Tinker what kind of sightinmg equipment do you have on the krag?

if it is open sights it could be difficult to hold elevation if you are looking foreward for your hundreth birthday.

I would think your load should shoot like a house afire. my first succesful center fire rifle was a krag carbine. paid $17 to stokes kirk in philidelfia if i rember right. all ways 15 grs of 2400 shot well. it did take several deer. acouple of elk. one brown bear and assorted other stuff.

Jim Wilcox

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billwnr posted this 13 September 2010

check out your throat and also your firing pin spring. Wheelweight is a good alloy for 1550 fps and 2400.

You may have a week firing pin. You may also have bad primers.

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JetMech posted this 13 September 2010

Tinkerer wrote: Today the 10 round group was about 3” wide and 10” tall at 200 yds.  The loads chronograph at about 1550.  I think Bill W has hit the nail on the head. Vertical stringing is normally an ignition problem. I'd replace the firing pin spring. Midway has a 22# Wolf spring that'll improve ignition and reduce lock time And, while you have the bolt apart, make sure everything moves freely, no old grease in there, and that the firing pin, in the forward position, protrudes about .050. That's not set in stone but's a good general guide. Excessive headspace with cases full-length resized to SAAMI specs will also cause ignition problems as the firing pin pushes the cartridge forward.

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Tinkerer posted this 13 September 2010

Wow, there's a lot to consider.   Thanks everyone for chiming in.  B) I will check the previous shooters results with Krags.  The barrel is brand new from CMP, made by Criterion.  I am shooting open sights, but I can typically hold the 10 ring (6 inches high) from the bench or from prone with my other rifles shooting jacketed bullets.  I have slugged the bore, but have not cast the chamber for throat diameter.  I'll put that next on my list. I'll check the other items, spring, firing pin protrusion, etc.  I had not considered lock-time. I am neck sizing the brass and have the OAL (3.090) about .020” back from the rifling.  This is my normal method with jacketed, I may need to rethink that for cast.

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Tinkerer posted this 13 September 2010

I was just skimming through the military match results and have a couple of questions. What is the “L” in the alloys?  i.e. 4WW-1L I noticed most shooters are sizing a 311 bullet to 310.  But some are sizing a 314 down to 311 and are getting some good results.  Do they do this to get a larger diameter on the nose of the bullet?  I thought the nose of the 314299 was .303.  Do these guys have oversize bores? My 311284 casts the nose at .300 and the bands at .3105.  The nose is a snug fit into the muzzle, but the bullet's nose is not engraved by the rifling.  Is this a problem? Thanks again for your patience and info.:cool:

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tturner53 posted this 13 September 2010

4 parts ww/ 1 part linotype. The target loads are generally seated out to just engrave on the lands, often single loaded. Maybe George D. will chime in, he knows the 311284 pretty good. The reason for the oversize bullets is to fit the throat. Measure the inside neck diameter of a fired case. You can use a bullet about .001” under that.

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RicinYakima posted this 14 September 2010

A lot of us are sizing to throat diameter, not the bore diameter. How big a bullet will fit in the fired case? OAL is a tight fit, there should be some resistance on the bolt closing. Remember cast bullets are very soft compared to jacketed bullets. They do not like to make a run up to the rifleing.

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Tinkerer posted this 14 September 2010

I'll check the fired case for possible bullet fit.  I was going to get some chamber casting material and try that too. In my initial post I was looking for info on alloys especially for faster muzzle velocities.  No one has suggested the Lyman#2 alloy.  I was hoping to use an alloy that I could buy or make from virgin materials.  Wheel weights aren't easy for me to get....Thanks again.:cool:

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JSH posted this 15 September 2010

Tinkerer wrote: I'll check the fired case for possible bullet fit.  I was going to get some chamber casting material and try that too. In my initial post I was looking for info on alloys especially for faster muzzle velocities.  No one has suggested the Lyman#2 alloy.  I was hoping to use an alloy that I could buy or make from virgin materials.  Wheel weights aren't easy for me to get....Thanks again.:cool:

I am no guru, but have shot a fair amount of cast in the past few years. When I was looking for speed I never had a lot of issues to speak of.I would take what you have and run them over the chrono until the accuracy goes or leading appears.

In my findings, bullet size and lube were a fair bit more important than a “special” alloy. FYI, I use WW with a bit of tin for 99.9% of all of my shooting. When I first started from my readings and other info, lino type was some kind of magic alloy. I have yet to run across anything where it works better or worse than WW.

On your vertical stringing, I am like some others and look at the rifle a good deal. If you think it is the load, try some jacketd in it and see if the same results are found.

jeff

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RicinYakima posted this 15 September 2010

I agree with Jeff, there isn't any magic alloy for speed,it is mostly fit and and keeping peak pressure less than alloy strength and a good lube.

92/6/2 alloy will be as good as anything. Lino is used by a lot of match shooters because it is easier to make more perfect bullets per hour of casting. But that is just because it has a defined freezing temperature.

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Tinkerer posted this 15 September 2010

Thanks everyone for the help. I'll work out the suggestions you've made and eliminate the variables. I'm confident this rifle will shoot.  Right now I've got to go load some BPCR rounds for my Browning Highwall.  I have a match this weekend.  :cool:

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Tinkerer posted this 10 October 2010

I have the Krag shooting well finally.  I switched to the 314299 mold and cast bullets from wheel weights.  With 16 gr of 2400, I'm getting good groups now.  2-3 MOA shooting prone with sling at 200 yds.  No more vertical stringing.  The bullets measure about .301-.302 at the nose.  I'm sizing the bands to .311.  I would still like to flatten the trajectory, but at least now I have a good load to tinker with.  This is a great rifle, I really like the action.:cool:

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