Heavy bolt lift - factory Berger ammo for reloading

[AirborneEScouter]

2 questions but first, some context:

For some reason or another, I have had a few cartridges give me issues in my custom Tikka from Berger's factory 215gr ammo in 300 wm. We all know Tikkas don't accommodate long COAL but I have some aftermarket mods to get an AICS mag and longer loaded ammo into the rifle. The barrel is a Bartlein and does not represent factory specs - I haven't measured the distance to the lands with this bullet but do not believe it is jamming into them. Every once in a blue moon I get a heavy bolt lift from this ammo but it is usually a rare occurrence - however, I was shooting yesterday and had it happen in about 40% of my shots (bolt required a little muscle to open but was definitely not a "stuck" feeling). The cases and primers looked ok but I am also a novice in checking for pressure signs. There was however an obvious imprint from the ejector plunger on the brass. Other items of note - I usually shoot suppressed but had it happen with suppressor removed as well. Also, it was 90+ degrees out and I was shooting in the sun. Only ran about 10 or so rounds through the rifle and this happened about every other shot towards the end of the shooting. I typically do not clean my rifle's barrel but try to keep the action cleaned though it has been a while since I've wiped out the inside of the lug contacts/opening to the chamber.

Do the aforementioned conditions yield to the contributing to overpressure? ie heat, dirtiness, supressed, etc - I feel like factory ammo shouldn't do this. I will be cleaning out my chamber before shooting again and may just pull apart a round and check ogive. This ammo is an absolute dart and shoots great typically, seems very strange to have the heavy bolt lift repeatedly.

Second - I have been collecting all this lovely norma brass with the intent to reload it once I get my setup complete. Do the plunger marks by themselves represent any safety issues for reloading if no other signs of cartridge damage? We are in the middle of a move and I do not have access to the spent rounds at the moment but can post later when I can pull them out of my bag

Any input is appreciated - thanks gents

 

[Kimber7man]

Carbon ring would be my first check

 

[Brendan]

Agree with the above. Clean action, throat, and barrel thoroughly, check for carbon ring.

 

[AirborneEScouter]

Makes sense, wouldn't have thought of that without a nudge

 

[Harvey_NW]

I would say the brass is fine. Inspect during prep and roll with it.

 

[Desert Dan]

Also, it was 90+ degrees out and I was shooting in the sun. Only ran about 10 or so rounds through the rifle and this happened about every other shot towards the end of the shooting. I typically do not clean my rifle's barrel but try to keep the action cleaned though it has been a while since I've wiped out the inside of the lug contacts/opening to the chamber.

I'm far from an expert but living in southern Arizona I have to deal with shooting in hot conditions or not shoot for months on end. Last weekend I experienced something similar to what you're describing. I started the day with an eight-shot OCW test to see where I encountered high pressure then switched to four 5-shot groups with three minutes in between shots to test for ES. 15 minute firing iterations at the range, 4 shots spread out over the iteration. No issues with the OCW and only got pressure signs - stiff bolt and clear ejector marks - with my last two shots, which were identical charge and seating depth. After that I shot the 5-shot groups (Five shots spread out over the 15 minutes) starting with the hottest loads and working down to prevent heat from possibly contributing to any pressure I encountered with the hotter loads. I randomly started getting pressure signs on the last two 5-shot groups with loads that were 1.5-1.75 grains lower than the charges that showed pressure during the OCW test when the gun was cool. It may be important to note that I only got pressure signs on the last few rounds of those strings, as well. In that time the temperature had also gone up nine degrees. The bore, chamber, and action were cleaned thoroughly prior to shooting, and every shot was out of unfired ADG brass.

This is not to say that heat was definitely the cause. Definitely proceed with caution and try again once you've ruled out a dirty barrel/chamber and checked for a carbon ring. I had one and they're no fun but definitely not the end of the world. A Teslong bore scope is a great investment. Also make sure you're not getting any cleaning residue or solvent on your cases that may be accumulating in your chamber as you continue to shoot. Good luck.

 

[AirborneEScouter]

Thanks for the input guys. Will give the rifle a good cleaning. Here’s a few pics of the brass for reference

 

[Desert Dan]

Oh yeah those are clear pressure signs. Update when you figure out what’s causing it.

 

[AirborneEScouter]

Cleaned the rifle thoroughly, all signs of pressure have disappeared. Of course, this ammo is no longer available either