.311 cast bullets in .308?


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Blakenzy
April 30, 2013, 04:20 PM
Is it OK to fire .311 lead cast bullets w/ gas check in a .308 Win rifle? Can this cause undue wear on the barrel? I have read comments elsewhere that say that it is OK, and others that say that the larger bullets will eventually ruin accuracy if I want to shoot smaller diameter .308 FMJ rounds later.

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Edarnold
April 30, 2013, 04:43 PM
No cast bullet is ever going to wear a modern steel barrel enough to "ruin the accuracy". If anything, after a few thousand rounds of cast bullets the bore will be smoother and more uniform than when it came from the factory.

Blakenzy
April 30, 2013, 04:58 PM
Well, I know manuals DO suggest using a larger diameter cast bullet to avoid gas cutting and leading, 0.001 to 0.002 larger... Lyman says that any larger is "counter productive" but explains no further... what would be meant by that? What would negative effects of a 0.003 oversize cast bullet potentially be?

Walkalong
April 30, 2013, 05:24 PM
It's hard enough to wear out a barrel with jacketed (Throat erosion is another subject), and nearly impossible with lead.

Blakenzy
April 30, 2013, 05:41 PM
So is there any compelling reason to avoid shooting a cast .311 w/ gas check in a .308 that I should be aware of? I suppose pressure might increase, but lets assume that appropriately reduced charges will be used.

USSR
April 30, 2013, 06:25 PM
So is there any compelling reason to avoid shooting a cast .311 w/ gas check in a .308 that I should be aware of? I suppose pressure might increase, but lets assume that appropriately reduced charges will be used.

Nope. I shoot .311" cast bullets in my M1 Carbine all the time.

Don

Don McDowell
April 30, 2013, 06:32 PM
Biggest problem you're likely to run into is whether or not the chamber on your rifle will let you use a bullet that diameter.
Next problem will be whether or not the bullet will get excessive finning making accuracy suffer.

2@low8
April 30, 2013, 09:54 PM
Don McDowell - Next problem will be whether or not the bullet will get excessive finning making accuracy suffer

I might know "finning" by another name. Would you explain? Thanks!

Don McDowell
April 30, 2013, 10:14 PM
Finning happens when the bullet is to large for the grooves, and the excess material is wiped on down the sides of the bullet creating fins on the base. Oft times the base will be caved in as well.
Some of the older Lyman/Ideal manuals had good pictures of recovered bullets that showed the affect to the bullet.

2@low8
May 1, 2013, 02:53 AM
Don - I know "finning" as "sloughing". I've been reloading for 45 years and I've never seen either term in any of the many reloading manuals that I have.

Since you have a reference, I will acquiesce to your term. Thanks for the reply..... Frankie

dragon813gt
May 1, 2013, 06:51 AM
If it chambers it will shoot. I typically don't go .003 over bore. But if I had some military surplus rifles that required it. I would start casting everything at .311 so they would work in everything I had.


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Blakenzy
May 1, 2013, 09:08 AM
Will finning or sloughing occur in a gas checked bullet?

Don McDowell
May 1, 2013, 11:05 AM
Yes, it can knock the gascheck loose, and that doesn't do anything for exceptional accuracy, won't hurt anything other wise, but it might make finding bughole sized groups a bit of a problem.

SlamFire1
May 1, 2013, 11:12 AM
When I measured the 30 caliber bullets I cast, they were all smaller than the mold size. Either the calipers were off, but I checked against match bullets for a standard and nothing was seriously off, or the bullets shrunk.

You end up sizing anyway, a little big is not a problem.

Don McDowell
May 1, 2013, 11:33 AM
Try casting those bullets a little cooler next time. Higher temps will make a bullet shrink more.

jaysouth
May 1, 2013, 03:24 PM
The OP said ".311 cast bullets in .308?
Is it OK to fire .311 lead cast bullets w/ gas check in a .308 Win rifle? Can this cause undue wear on the barrel? I have read comments elsewhere that say that it is OK, and others that say that the larger bullets will eventually ruin accuracy if I want to shoot smaller diameter .308 FMJ rounds later."

You should not shoot any cast bullet of any diameter until you slug your barrel. What is the diameter of your barrel?

Certaindeaf
May 1, 2013, 03:34 PM
Some guys here seat a gas check onto a .309 + etc. by seating it into the sized/belled case mouth.
Never done that but they say it works well. Also, sizing, (per se) is not "necessary".. indeed, many say that any sizing is detrimental to accuracy.

blarby
May 1, 2013, 05:24 PM
Yep. Its just fine.

RPRNY
May 1, 2013, 05:44 PM
Yes you can without safety concerns. The higher potential pressure is somewhat offset by less friction from lead. If hand loading, lead will, generally speaking, benefit from a somewhat faster powder and you should work up from start jacketed loads. You will likely find a lighter charge than would be best for jacketed will be best for lead. With .311 in a .308 barrel (if it so slugs ) of 22-24" length, you may be able to use the same powder you would for jacketed. Again, with a shorter barrel, a slightly faster powder might work better. Suggest that even with GC, you stick to moderate velocities - will help avoid sloughing/finning and leading in general. If you can find the right powder/velocity combo, you will have excellent results . Slugging your barrel will help with future lead orders or casting. Generally speaking (micro groove aside) .002 over bore works best.

GooseGestapo
May 2, 2013, 01:18 PM
After shooting various cast bullet styles/diameters through .30cal rifles for over 30yrs, I've settled on .311" for ALL my .30 cal's.

I started using .311's when working with some .32acp cast 78gr RN and Bullseye powder with a .30/30. at 50' I was getting 1-hole groups and at 50yds was getting far better accuracy than I'd ever seen from this particular rifle, to include jacketed bullets.

I scratched my head and cast some 150gr FNGC (Lee .308 FNGC, cast to 160gr) sized/lubed them to .311", and loaded them over my typical load, 28.0gr of IMR3031 at the time. Viola !! near MOA groups at 100yds w/scoped rifle. Now I use RL15 for equal or better accuracy and even higher velocities (2,200fps hunting load).

I've also used them in several .30/06 with equally accurate results....

Like another poster mentioned, if the bullet will readily chamber after loaded into the brass, it'll shoot fine. In the matter of .30/06 and .308 it's possible that some mil-surp brass may have some overly thick necks that could cause some problems. I also saw this with some PMC brass in a 7mm08. I neck-turned the brass and "fixed" that problem...

For neary 20yrs, I'd followed the Lyman advice of 0.001" over bore with cast bullets; ergo I used .308 and .309" sizing and "accepted" the results w/o questioning the recommendation.

I've used as large as 0.313" in the .308's (.30/30, .308, .30/06) and as long as they chamber easily, they're fine. I recently loaded for a friends .303Brit. I started with .314" and decided to try some .311". They too shot fine, so I only use one size for simplicity, 0.311. They've even shot very well through a Moison-Nagant.

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