.308: soft point hunting bullets in an autoloader?


PDA






ny32182
November 24, 2004, 09:39 PM
So I'm planning to break in my new SA58 next week. DSA calls for a 20 round break in, and advises against the use of mil-surp ammo for the break in. I looked for some factory FMJ, but all I can find locally are soft point hunting loads. I got a box of 20 Winchester Super X's. I chambered one of them, and upon unloading it, noticed that the soft tip was rather deformed. I have not had this issue with .223. Will a deformed tip cause accuracy or other problems? Should I shoot this ammo or not?

If you enjoyed reading about ".308: soft point hunting bullets in an autoloader?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
GooseGestapo
November 25, 2004, 06:20 AM
Depends on what you're calling deformed.

If only the small lead area shows some irregularity, it dosen't significantly affect the accuracy. If it looks like it was thrown up against a brick wall, maybe it will.

I'm not familiar with your rifle, but likely, a mil-surp s/a will probably ding the bullet tip going up the feed ramp into the chamber and slightly deform it anyway.

I'f it's in .308, then you could shoot some of the match loadings in either 168gr BTHP or 190gr HP. These will deform much less than a soft point.

Any U.S. or similar ammo with cup jacket and lead core should suffice for break-in. I think what they were telling you is don't use steel jacketed mil-spec. ammo for the breakin.

I wouldn't use it (mil-surp ammo) in a quality firearm anyhow. Save it for the old mil-surp guns.

Mark whiz
November 25, 2004, 02:25 PM
Winchester White Box 150gr FMJs or PMC 150gr FMJs would be perfect for what you want to do. Those ought to be pretty easy to find at a gun shop or even Wal-Mart.

Semi-autos CAN be rough on the tips - you oughta see what my M1A can do to the Plastic ballistic tips on Noslers & Hornady SSTs. Having the soft lead tip getting nicked or compressed some, can hurt accuracy a little for match work - but unless it is just mangled, you probably won't see a change greater than 1 MOA.

musher
November 25, 2004, 03:33 PM
FWIW Mark, I think your estimate of the effect of bullet tip deformation on accuracy might be as much as 10x too high.

Harold Vaugn examined the effects of bullet tip deformation on accuracy in 'Rifle Accuracy Facts' (worth reading!) pp 216-217.

The actual effect was too small to measure experimentally. Trajectory simulations (6 DOF) done with a 45 degree slice taken off the tip of a 150gr .270 soft point bullet to simulate tip deformation of a hunting bullet predicted an increased dispersion of .135 inches at 100 yards. It would be hard to see this in a 1 moa rifle. Not enough to worry about with the DSA for sure, unless it's a whole lot more accurate than mine.

Typical deformation seen in HPBT match bullets resulted in a predicted increased dispersion in the 3-5 mil range (.003-.005 inches) .

at any rate, I thought it was interesting. Certainly convinced me to stop worrying about tip deformation in the rifles I shoot.

NMshooter
November 25, 2004, 04:14 PM
www.ammoman.com

Eric should have what you need. :)

Peter M. Eick
November 25, 2004, 06:15 PM
Out of my M1A supermatch, I was really battering the last few rounds of a 20 rnd mag with Seirra's 150 grn softpoint. I don't remember the exact load, but what I did was shoot the first 10 into one target and the second (noticeably battered) into another target.

I could not detect a lick of difference. I called seirra about it and they said basically at less then 200 yrds you would probably never know it.

Frankly I would not worry much about it for "short" ranges. It looks bad but does not really matter much.

RooK
November 25, 2004, 07:37 PM
One guy in Rifle tested this theory a few years ago by cutting bullets length-wise with a bolt cutter. Those that weren't too deformed he loaded up and shot. They still grouped within 2-3MOA. So surely a small, deformed tip won't make that much of a difference in a battle rifle.

Roadkill
November 25, 2004, 09:04 PM
I load 30.06 for an 03,03A3,P17, and M1. Use 4895 and 150g btsps for all. I have also used 150g rnsps in all before too, same as with my 30-30. The Garand has fed them all with no problem. I have a DSA STG58a that I'll use sps when the cheap surplus ammo runs out. I pay more attention to cartridge oal and case length than to the the projectile with semi autos.

rk

wasrjoe
November 25, 2004, 09:20 PM
I shoot wolf SP out of my AK all the time. (The last 1k rounds I bought were SP.) I have not had a problem with accuracy at all (still groups poorly, but no more poorly than it did ;))

GooseGestapo
November 25, 2004, 09:39 PM
Addendum.....

FWIW;
Several years ago I had a GunDigest,loading manual, or some such publication discussing this issue. It had some high speed X-ray photo-micrographs of a Sierra soft-pt and a bullet much the same as a Speer MagTip or a Rem. Cor-lokt (gettin too old to remember which!).

The tip of the Sierra had "slumped" due to the inertia and friction heat of acceleration and barrel passage that showed the tip of the bullet almost flattened to the same degree as the "mag-tip" bullet.

These factors partially explain why the tip deformation is not as significant as might first be imagined. Also explains why Speer's flat nose .30 caliber bullets have such a high ballistic coefficient as compared to many other such bullets. They (Speer FN's) have a "spitzer" type secant-ogive with a smaller exposed lead area- both thickness and diameter.

The other part of the explanation is that with a properly designed spitzer style bullet, the center of gravity is in the rear part of the bullet and the small deformations in the nose are closer to the center of rotation and away from the center of gravity.

Additionally, with super-sonic objects, the frontal shockwave propagates from the front such that it negates some effects of the tip irregularities.

All these explain why the plastic tiped bullets "behave" so well.
(The plastic tips actually have higher strength modulus and melting temps than lead. If you don't believe me, look at the tip after recovery from a game animal. I have some from 100gr Nosler .257's, and one from a 35gr Horn. V-max from a .22 Hornet @ both at 3,150fps m.v that killed a doe DRT from a heart shot that look almost as if they could be reused! -of course the jackets and lead cores essentially disintegrated.)

sigman4rt
November 25, 2004, 10:21 PM
Itried and liked the Winchester and Hornady polymer tipped factory ammo. Now when I handload for practice or hunting I use a Hornady 168 gr A-MAX or Winchester polymer but mostly 168 or 175 gr. A-MAX. The tips don't deform and they are more accurate than Sierra match bullets.

goon
November 25, 2004, 11:34 PM
I have loaded quite a few Speer 165 grain BTSP's for my FAL. I have to use handloads on the steel silouhettes at the range because milsurp is banned on them and factory ammo is too expensive.
The nose on them does get banged all to hell on getting fed into the chamber and then again when the bullet goes past the shoulder in the chamber. It is bad enough on the shoulder that you have to yank back on the charging handle and let it go from its most rearward position or it won't chamber the first round. The rifle will cycle and feed them under its own power but it won't chamber the first round with just the mag release.
To answer your question, I have noticed no difference in accuracy out to 300 yards. It is still minute of steel pig at that range.

ny32182
November 25, 2004, 11:50 PM
Ok, thanks for all the opinions. I will shoot my softpoints when I get a chance.... going to be using them for the initial barrel break in/sighting/proper gas adjustment all at the same time. They are only 6 grains off from the Aussie surplus I have, so hopefully the POI won't be that much different.

If you enjoyed reading about ".308: soft point hunting bullets in an autoloader?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!