My dad called this morning and said that he had goofed and used the wrong powder in his 270WSM. He used 66 grains of H4350 instead of H4831. That is 5.5 grains over the max.

The primers were flattened, but what really made him think was that after resizing the necks, the cases would not chamber in the gun.

The question he has is: How can he tell if the gun is damaged?

BTW, the loads shot less than 1" groups.

What gun is he using?

Yes, the gun is irreparably damaged and unsafe to fire under any conditions! The scope is likley toast, also. Please send the gun, scope, ammo, brass, and dies to my dealer (FFL info provided in PM), who will charge you only $50 to demill the gun and erase it's serial number and owner's name from the Secret Department of Homeland Security database.

Thank god you asked this question before someone got hurt!

It's a Winchester synthetic like what Walmart sells.

Stonecreek,

Is there supposed to be a "d" between stone and creek?

The piece of brass may be dammaged.

There is some argument if you can work harden a rifle with 1,000,000 overloads that do not reach plastic deformation [when the rifle does not change size or shape].

quote:

The question he has is: How can he tell if the gun is damaged?

It certainly wouldn't hurt to have the headspace checked.
In all probability it's not damaged. I had much worse happen to a M-70 and it was undamaged.

I doubt the gun was subject to stresses in excess of what it was proof tested with. Given that the action didn't seize, I'd continue to shoot it.

quote:

Originally posted by P. Steve Morgan:
It's a Winchester synthetic like what Walmart sells.

Stonecreek,

Is there supposed to be a "d" between stone and creek?

Folks, we have a winner! Best comeback I've ever been assaulted with on this board.

Which merits a straight answer to your question: No, the rifle is fine. If the action opens and the brass is enough intact actually be run through a resizer die, then there will have been no stretching or deformation of a modern rifle's steel.

The reason the case will not readily rechamber, even after full length sizing, is that the resizing die is not really a full length sizing die in that it does not resize the bottom half inch or so of the brass (this is what a "small base" die does). Hence, the brass base swollen under the excess pressure from the mistaken powder is not resized and will not reenter the chamber.

Thanks everyone,

I'll forward the info. If by chance something does happen, I'll be sure to post.

quote:

Yes, the gun is irreparably damaged and unsafe to fire under any conditions! The scope is likley toast, also. Please send the gun, scope, ammo, brass, and dies to my dealer (FFL info provided in PM), who will charge you only $50 to demill the gun and erase it's serial number and owner's name from the Secret Department of Homeland Security database.

There are two possiblities. It could have stretched headspace, a swollen chamber, or both. However, NEITHER of these would impair putting a cartridge into the chamber - it would in fact make it too easy to close the bolt, as the chamber space would be enlarged in all directions!

You should, however, have it checked by a gunsmith if you can't tell if the chamber is too big by yourself!

Try chambering a NEW, empty case. If it chambers correctly, that will tell you something!

(IF the primers were merely flattened, the primer pockets were not stretched or blown, the case heads were not blackened/distorted, he was able to open the bolt by hand and the fired case came out as it should have, chances are that the rifle is OK........ Pressures high enough to damage the rifle will enlarge the primer pocket, and damn near blow the head off a cartridge case before pressures get high enough to hurt a modern bolt-action rifle! The brass is the weak link.....)

I once fired a Ruger 77 338 mag with 68 gr of 3031 instead of 4831.

Finally got the bolt open, but no other damage.

Give your dad a pat on the back for having the smarts to ask and be concerned. I run into too many folks that would not think the situation trough and would not address the potential safety of the rifle.

My experience with the Short Mags and SSMs is that the brass is hard to chamber after firing each time--even with factory loads. Resize the brass, and try and seat a new primer. If it feels right-great. If it just falls into the primer pocket--they're enlarged and the brass should be relegated to the recycle barrel.

Have the rifle headspace checked--and if normal, shoot away.

Here's a link that may shed some light on this subject. Reloading: sizing issues, tight chambering

quote:

Here's a link that may shed some light on this subject. Reloading: sizing issues, tight chambering

sounds like another reson to stay away from the short mags.

Against my better judgement, I took in an A-Bolt in .243 WSSM for an accuracy load workup and to load some 55-gr Ballistic Tips for the wife to shoot for familiarization with minimal recoil. I'm going to the range this week with the BTs--and after I find a load that shoots OK, I'll start with the Spire Points, Barnes Triple shock, etc for a hunting load.

Sure hope I don't have the problems I've had before, but then I've already made the mistakes and shouldn't do it again, right?