Attempting HV through my Mosin

BHuij

Active Member
#1
Hey everyone--

TL;DR: Really terrible results with loads ranging from 37-40 grains of IMR 4895 in my 91/30. Using the Lee .312" 185gr RN with a gas check and Felix lube. Alloy is COWW heat treated and quenched to ~19 BHN. It's not just a bad rifle; I've had good results with other loads. Help me figure out why so I can fix it?

I got inspired to see what I can get out of my 91/30 beyond the standard mouse fart loads found in the Lyman Cast Bullet Handbook 4th Ed. I already worked up a pretty decent plinking load using the Lee .312 185gr RN mold and air cooled, powder coated COWW alloy, with an aluminum gas check. 23 grains of IMR 4227 got me reasonable accuracy out to 100 yards. Not anything special, but minute of steel plate at least.

However, I want to use this as a hunting rifle. I don't have a chrono, but a little math tells me my IMR 4227 load is somewhere in the neighborhood of 1750 FPS. That translates to roughly 1100-1200 foot pounds of force delivered to the target, depending on range. Probably enough to handle a deer, probably not enough to cleanly and humanely take anything much bigger.

So I decided to try for something hotter. After lots of reading and research, I figured I'd try using heat-treated/quenched COWW alloy aged for 2 weeks. It was in the oven for 1 hour at 425 degrees F, so according to the LASC chart that puts me at roughly 19 BHN. Ideally able to withstand a lot more chamber pressure without deforming compared to air-cooled.

Unfortunately I couldn't powder coat after heat hardening like that or else I would anneal the bullets and undo all my work. So I pan lubed with Felix. Which was messy and sucky, but it worked and filled the lube grooves.

I seated just deep enough to cover both lube grooves, and tried loads of 37, 38, 39, and 40 grains of IMR 4895. Once again, no chrono, but I can estimate velocity to be around 2140, 2190, 2250, and 2300 FPS respectively. Each group got 10 rounds, fired off sandbags at 50 yards, using open sights.

I barely made it onto the paper for 2 or 3 shots out of each 10, and the shots that did were all over the place. Honestly the best I can tell you was that it appeared to be shooting high as a general trend, but the groups were nonexistent, and the bullets were just going everywhere. I tried holding low, high, left, and right at varying distances from my desired POI, and almost nothing worked. I'm not a crack shot with a rifle by any means, but I'm not totally incompetent, and I'm 100% sure that this was the loads not working, not just me. I didn't even bother firing the 40-grain batch. I wasn't getting anywhere with the first three loads, and my shoulder had taken a beating already. As a side note I ordered a rubber butt pad online as soon as I got home ;)

SO, I need your help to diagnose my issues here.

Here's what I believe I can rule out:
-Bad rifle, bad bore. I have seen this rifle do just fine with PPU FMJ factory loads at 100 yards. I ordered 60 rounds of it so I would have some brass to reload. I've also seen it do just fine with my IMR 4227 load. I'm not trying to hit sub-MOA, but <4 MOA at 100 yards would be great for HV by my estimation, and certainly "on paper at 50 yards" is not outside the grasp of this rifle.
-Poorly zeroed sights. There was no rhyme or reason to where these bullets were impacting. As I mentioned before I tried holding sights at center, left, right, low, and high. Once in a while a projectile would hit the target. It was never repeatable.
-Undersize bullets. My bore slugged out to .314" in the grooves using a fishing weight. Since I expanded the cavities in my mold, my bullets drop at .315" using COWW. I usually size after powder coating back down to .315" Since these weren't PC'd, I just left them as cast.

Here's my list of suspects. Hopefully you guys can suggest which are/aren't likely factors in my piss poor results - and which ones are the first ones I should fix.
-Poor bullet fit (from a more advanced perspective). I have not yet done a pound cast, but maybe the bullet is really poorly supported as it jumps the throat to engage the rifling, and this is causing it to deform excessively?
-Seating projectile too deep in case neck. I think there was a pretty hefty amount of bullet travel through the throat before the bullet started engraving in the rifling. That certainly wouldn't have helped anything. I just felt weird about leaving a lube groove exposed when it actually had lube in it.
-Alloy too weak. This goes hand in hand with poor bullet fit in the sense that perhaps mixing in some linotype would help the bullet weather the first few microseconds of launch better? I don't want too brittle of a bullet for this load if I can avoid it; want to keep the terminal ballistics really good for hunting purposes, and ideally that means the bullet stays reasonably ductile.
-Wrong powder? I kinda feel like I did my homework on this one, but I'm not opposed to trying something like 3031, 4064, or Varget if someone can convince me that IMR 4895 is a bad choice.
-Wrong primers. Forgot to mention that when I first started loading for this rifle I accidentally bought 1000 CCI 250 LR magnum primers instead of regular large rifle. I'm poor, so I'm still using them. Could the additional pressure be deforming my bullet?

I'm thinking for the next tests, I'll make the following adjustments:
-Shoot at 25 yards. Yes I'll feel like an idiot, but at least I'll have some semblance of an idea where my bullets are going. I can stretch further out when I get closer to a working load.
-Go back to powder coating. Turns out you can heat treat after powder coating. I already have some PC'd 30 cal bullets that I heat treated/quenched to a target hardness of ~20 BHN. They'll be ready to shoot in about a week. Even if the Felix lube was working (and I'm not convinced it was at these velocities), doing lube by hand or in a pan sucks.
-Start a bit lower and work my way up.
-Seat out to the lands again.

Any insight or suggestions are appreciated.
 
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Ian

Well-Known Member
#2
4895 will get you to maybe 2K fps before you start having problems.

Two-diameter bullets with a long nose almost 99.999% of the time are completely worthless for exceeding 1900 fps with any hope of accuracy. I used that same Lee bullet cast from straight, air-cooled COWW alloy in my .302x.310" model 70 classic '06 for years and killed a few deer with it. Felix lube, 39.5 grains of H4350, CCI 200 primers and LC brass. It was dirty and only going about 1950 fps but would put ten in 1.5 MOA at 100 yards all day long, group after group, from any position and would do it next week or next season on demand without cleaning the bore, ever. It tended to pencil through deer but I knew where it was going to hit and they never went far with a good boiler-room shot.

Guidelines for HV shooting with accuracy: Fill the throat, fill the chamber neck, size brass to fit chamber snugly, use an in-line seating die, neck size only enough to get consistent neck tension around .002" with hard bullets and .0015" with softer bullets, match the alloy blend and temper to the rate of pressure rise (could write a book on that one), use a good lube (you did), seat gas checks perfectly square, cast perfect bullets with flat, square bases and no voids, cull bullets with a scale AND a micrometer, use a slow a powder as you can get to burn consistently in the "system", the list goes on.

Start with a pound cast and let's see what you have to work with.
 

BHuij

Active Member
#3
Sounds like pound cast is my next stop.

If I’m reading you correctly, it sounds like you’re saying the Lee bullet I already have a mold for is probably going to be a no go for HV?

I’d like to avoid buying another mold if possible. However I’m not opposed to modifying this mold further. Is it probably just a matter of filling the throat better, or are we talking totally bad design for high velocity at all, not workable?
 

fiver

Well-Known Member
#4
yes.^^^^.
let's start at square one.
generally what happens is you have enough alloy, you just ain't got no support and the fast pressure rise just ruins everything.
it actually ruins it twice.
the first time is when the base moves forward and outward, and the second time is when the base is smushed back down to fit the barrel.
forget 4895 think more like rl-22 or even slower.
 

BHuij

Active Member
#8
Okay, looks like I can pick up RL-22 or RL-25 locally for $30/lb, which is fine. Weirdly enough, I can picked up RL-23 from the same store for $25/lb. Near as I can tell, RL-23 is just RL-22 but with extra magic resistance to temperature fluctuations changing pressure.

No point getting a new powder though if my bullet profile is just flat out not going to work past 1.9k FPS. So step one is pound cast. We'll go from there.

Waco, to answer your question, I think a 170gr would be great in the Mosin, at least as far as weight is concerned. Standard issue milsurp ammo uses a 148gr projectile I believe, so my 185gr which I'm already using is heavy for caliber. Are we talking about this one? http://noebulletmolds.com/NV/produc...ucts_id=915&osCsid=iir778tlcg909rshd7c0b42dv4

Does it come any fatter than .310?
 

fiver

Well-Known Member
#9
the XCB is about .003-4-5 too small, and it's meant to work in the 0-6 throat, it just happens to work in the close-nuff 308 throats.

we are trying to figure out how to slide a bullet the first 1" without distorting it.
powder is easy, there are at least 10 I can think of that will work and I have never had a Moisin.
 

BHuij

Active Member
#10
Yeah I have that list of powders ranked from fastest to slowest burning. RL-22 is down on the slow end, but there are plenty of other ones in the same zone.

But yeah. Let's worry about pound cast and getting a bullet that works first.
 

Ian

Well-Known Member
#11
This one would work for a basic shape and proportion if it were scaled up to fit: http://accuratemolds.com/bullet_detail.php?bullet=31-177BG-D.png

Or hit the "easy" button with this one, again, scaled to fit your rifle: http://accuratemolds.com/bullet_detail.php?bullet=31-175B-D.png

The concept is fill everything with bullet.....neck and throat. The corollary to that is DON'T try to depend on the tops of the lands to support the nose (because they WON'T), so choose a bullet that has as little of the nose as possible be smaller than groove diameter and still have a point-ish front end. Bore riders are a trade-off and work-around for rifles with short throats.
 

BHuij

Active Member
#12
Makes sense. I like the meplat on both of those for hunting purposes. Sounds like the Lee mold is just asking for trouble since it's basically two driving bands in the back and then 8 miles of unsupported nose.

Guess I'll save that 185 mold for plinking and pick up something with more base and less nose when I'm ready to get serious about HV in this gun.
 

Ian

Well-Known Member
#13
Everything has limits. The bore riders do great at 1400 fps, IF they fit tight. Look at the groups Ben shoots with them, one ragged hole with just about anything he owns. Look at his loads, 7-8 grains of slow pistol/shotgun powder. He works within a certain zone and gets him excellent results. At 2,000 fps and up things get a little more tricky due to the increased stresses involved and it's not so easy to keep a delicately-supported bullet straight in that critical first inch of travel. The case neck can't support it straight if there's too much chamber neck clearance, and the lands can't either, so the bullet can actually yaw before it even starts to move forward out of the case. One of the best solutions to the problem is don't give the bullet anywhere to go but straight, make it met solid barrel steel on all sides, in as many places as possible. Then make concentric ammunition.

There are other ways to do this, but they can get complicated and take a lot of work. Semi-autos have their own sets of challenges, not the least of which are not really being able to get the cartridge in line with the bore to start with, and needing free fit where the bullet doesn't actually touch anything except the case neck until fired...both factors resulting from the necessary operational clearances of the ammunition.
 

BHuij

Active Member
#14
Okay, I'm back with a pound cast. I followed the instructions in your excellent series of write-ups:

1. Heat fired case neck to dull glow
2. Fill case up to close to the top of the neck with hard-ish alloy (COWW)
3. Cast a bullet from soft alloy (I used SOWW)
4. Insert into the chamber, force bolt closed, tap from muzzle end with a metal rod/hammer until it stops moving and feels really "solid"
5. Extract case and bullet to measure

I always assumed my SOWW alloy would be in the neighborhood of 6 BHN, but having recently obtained a Lee hardness tester, a few bullets I cast from pure SOWW alloy actually tested out to about 8.4 BHN (this is a couple of weeks after casting).

Anyway, here's what I found:

Mosin Pound Cast.png
 
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popper

Active Member
#15
Use hornady Cu GCs. I tried 'home-made Cu GC' that don't work for accuracy at HV.
Your pound cast shows 317 tapers to 312 but the groove is 314? My guess is 317 taper to 314 (groove) So basically a really long throat. I use a 31-185C in my BO that has the long throat, works well. Pretty much fits my 30-30 too.
 
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BHuij

Active Member
#17
So then a mold from Accurate that tapers from just shy of .317 to just shy of .314 ought to be a good starting point for HV?

Any reason I couldn't take my existing Lee mold and expand it out with valve grinding compound so the driving bands are more like .317, and the "bore riding" portion goes out to .314 as far out as the origin of the rifling? It would take some elbow grease, but I have a lot more elbow grease on hand than dollars to pay for a new mold :D

I have successfully expanded all the cavities on a 6 cavity mold I use for 9mm from .356 to .359 before, no problem. This is a bit more ambitious of a grind, but worst case scenario I'm out $25 for a new 2-cavity mold from Lee.

Only concern is the bullet would probably go from 185 grains to closer to 200. "HV" with a 200gr bullet might be more like 2100 or 2200 FPS. If I'm going to be firing a projectile that heavy, it makes sense to shoot one with a higher BC.
 
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Ian

Well-Known Member
#18
Can't tell much from that pound cast, your alloy was too hard for the amount that you hit it and it didn't upset fully into the ball seat area. Try to get some softer material for the bullet and try again until the lube grooves mostly collapse. You'll want the annealed case neck to upset as well so you can measure your chamber neck near the front. I like to start a gas check down the muzzle and push it all the way against the bullet with the rod, then upset the slug with a 2# hammer, not hitting the rod hard, but letting the hammer fall from its own weight.
 

fiver

Well-Known Member
#19
that area behind the rifling being .002 smaller is an indicator of not enough lead movement or a big problem.
most of the newer SOWW's have stuff in them now, they ain't like the old ones that just had a little tin and pretty much nothing else.
you could just do a barrel slug to see if it gives 312 down there and go from there.
 

Ian

Well-Known Member
#20
I would think if it was bulged ahead of the throat he would have de-bulleted and had a time getting that throat slug out of the barrel from the breech end, so I'm leaning toward not enough lead movement.