Gentlemen,
I am getting my M70 back from the gunsmith tomorrow, where it was for a trigger job and a chamber check, since every hand load I have fired through it has cratered the primer. I had a bunch of Rem 180 PSPCLs, so I used my Hornady book to find a good, safe place to start loading, and worked up from there. I am using IMR 4350 at 54.0 gr. and I have no idea about velocity. I went all the way up to 57.0 grains, but accuracy was not good, so I stayed at 54.0 gr. I should add that even the "light" loads, 51.0 grains, cratered the primer. I know that I really shouldn't use Hornady data for Rem bullets, but I did and I can't change it now. The headspacing is perfect. I learned that today. My smith said that the load was too hot. But every stage cratered the primers. What do you all think? Could it be an oversize firing pin hole? My last group was 5 in less than an inch outside to outside, so I really don't want to change anything. The other thing that had me concerned for a while is that I was FL sizing, and I am getting split necks after 4-5 firings. I am only partially FL sizing now. I'd love to hear what you more experienced gentlemen have to say.
Regards,
Graham

It could be a good idea to say which caliber your rifle is chambered for, even if I guess it's a 30-06.

If there is just cratering and no flattening of the primers, it looks like an ill fitting firing pin.
Ask the smith if he did any work on the firing pin or the bold face.

Other then an oversize firing pin hole, another cause of cratered primers is a weak mainspring. Plays hob with groups too.

A recenmtly acquired Ruiger No. 1B in .30/'06 is quite satisfied with 57.5 grains of IMR 4350 and the 165-grain Nosler BT for 2900 FPS from a 26" barrel. I don't think 54 grains of that powder is too much with a 180-grain bullet. Your 54-grain load should be giving you right about 2700 FPS, the standard factory MV for a 180-grain '06 bullet....

As mentioned above, cratered primers are not a reliable indication of excessive pressures. Neither are split necks, which are due to brittle brass that has been work-hardened in the sizing process. You need to anneal those case necks.

All of these signs of pressure even a the low end of the loading scale and you continued to load them hotter? It splits necks etc you still continue to shoot it?

I agree with the others, the cratering may be a weak spring or overly large hole. The absence of any flattening and the load being used doesn`t add up to high pressure to me. The rifle "should be able to handle loads in the range you are loading. I use 56 grs / 180 gr Hornadies in my `06 and get long case life with no case problems. No two rifles react the same though.
The split necks are not usually a pressure sign either. The cases sound like they are being overworked causing them to split. The partial sizeing will reduce the working of the body and shoulder but the necks will still be subject to stress. Then again you may have a bad batch of brass that didn`t recieve a proper annealing.

I had a similar problem with my Model 70 25-06.
I noticed it much more with CCI 200 primers even though I've never had a bit of trouble with them in other rifles. I started using Fed 210 in this rifle and its not nearly as bad. I'm not saying its a cure for what ails ya but it made it tolerable in my situation.
By the way, I've settled on 54.0 grains of 4350 with 180 grain bullets in my 30-06. It shoots well so why push the envelope? If I need more speed I just step up to the H&H or the Weatherby.

Does it crater primers with factory loads? If so, there is likely no pressure problem, but as others have suggested a problem with the firing pin/hole.

Remember, anyone can hang out a shingle and call himself a gunsmith, and even many of the better gunsmiths know little or nothing of handloading and interior ballistics. If it turns out to be a firing pin/hole problem, take it to another "gunsmith" for remedy.

Gentlemen,
My bad. The rifle is a 30-06, and it did not crater primers of some soft point Yugoslavian amunition that I bought just so I's have something to shoot before I actually started handloading. I have been using CCI 200 primers. Maybe a different primer will solve the problem.

Jay Johnson

quote:

All of these signs of pressure even a the low end of the loading scale and you continued to load them hotter? It splits necks etc you still continue to shoot it?

I started at 50.0 grains of IMR 4350. Hornady min for their 180 gr. bullets is 48.1, and those starter loads cratered as well. There was definitely no excess with that load! Thanks for your cautions, though.

Thanks for the input,
Regards,
Graham

I shot 55 gr. IMR4350 with 180 gr Sierra 2160 bullet, in a 24" barrel and expected 2731 fps, but only got 2550 fps. So I gave up becuase it was too wimpy.

I also shot that day in that rifle, 55 gr IMR4895, 150 gr Sierra 2125 bullet, expecting 3025 fps, but got 3187 fps and loose primer pockets, so I gave up on that load as too hot.

quote:

Originally posted by tnekkcc:
...I also shot that day in that rifle, 55 gr IMR4895, 150 gr Sierra 2125 bullet, expecting 3025 fps, but got 3187 fps and loose primer pockets, so I gave up on that load as too hot.

55 gr of IMR4895? My Sierra manual #5 suggests 51.7 gr AS MAX! Don't be surprised to have loose primer pockets.

A cratered primer alone is not a sign of anything except a mass produced rifle. In conjunction with other signs --as posted-- it does mean something.
54-55 grains of 4350 should be top end for your 180's. The 30-06 with a 180 core lokt bullet has probably killed everything walking in North and South America. Even at a "wimpy" 2500fps