Well, I have a 300 Win Mag and I reload for it. I use the 180gr Nosler Partition and I use Nosler #5 manual maximum loads. I am shooting a 180 NP over 75.5 grains of RL22, and I am using CCI 250 Mag Rifle primers. I seat my bullets to 3.360" which is .02" over the SAAMI suggested OAL. I have had no problems with this load until now. I have noticed a 'ring' around the firing pin hole. The primers are leaving a ring, almost an indention in the bolt-face. The primers themselves arent showing any major signs of flattening. I am lost in why or how this is happening. Now, for question #2. The 3.360" OAL length has been working fine, no chambering problems at all. But today I went to put one in the chamber on the slim chance we see a deer on our way up to sight in the SKS. The bolt wouldnt close. So I thought that I may have not closed the press all the way when seating the bullet, so I took that one out and tried the next one in the magazine. No luck. I tried 6 bullets altogether, none chambered. Those 6 bullets are out of a batch of about 50 rounds that I reloaded. I had shot about 25-27 of that batch last week to sight in my rifle. How could these rounds "grow" in length?

Are your primers seated at or below the base of the case? Many primer pockets need to be cut to the proper depth with a special tool.

Measure the LOA of the rounds that will not chamber now, are they longer now? That load is a compressed one according to my internal program for a FL sized case. Have you FL sized your cases?

The ring on the bolt face could be from a leaking primer but in your case my guess is that its from primers not seated deep enough.

Don't slam your bolt closed until you determine that your primers are seated deep enough.

If you are not satisfied with our help call Sierra's toll free number as this is a safety problem.

In case you didn't notice, the question was posted by my brother, David Boren. He was used to this computer being signed in for him so he posted the question under my name.

The answer was really quite simple. The other night we cleaned all our rifles at the same time. Since we own both a .270 Win Rem ADL and my brother has his .300 Win ADL. His rounds wouldn't chamber cause he put the .270 bolt in his .300 Win

He is trying to blame it on me but I would never be that stupid

Thanks for the reply (s) anyway.

I knew it was that all along.