Oh Jim, Master of the Reloading Bench and educator to the masses.
I am reloading 6.5prc. I am using Lapua brass. Some may be Berger Elite Hunter once fired from the Seekins Havak Bravo (which I sold when I bought the Slam). Some could be once fired from the Seekins Slam. Since I don’t reload massive volumes, I usually take the sized and trimmed cases and run them through the action of the rifle (Slam). Out of 41 cases, 26 the bolt closes very easily. The other 15 cases the bolt closes, but is noticeably more difficult but still closes.
I have compared measurements, Trimmed Length, Ogive, all are less than 1/1000th difference. You may recall when I first started reloading, I had a very hot load. A few blown primers, heavy bolt lifts. I don’t know if any of the cases were from that, but when resizing I was getting some die marks at the base of the case. I wonder if the hot loads could have expanded the cases causing a little more being required to close the bolt. Those hot loads were shot through the Bravo. I know that cases will conform to the chamber they are fired from.
Any thoughts? Think these are safe to shoot? Lapua brass seems more substantial than Hornady.
All I can really think of is the hot loads expanding some portion of the case head, which isn’t changed in a die. If all other measurements, particularly the shoulder, are the same, that’s all I could imagine.
Any time it’s tough to close the bolt, there’s some risk of the pressure spiking. For me, if the bolt doesn’t close easily, I don’t shoot.
If you’re sure the bullet isn’t contacting the lands, it’s been full length resized, the brass is trimmed properly, and the shoulder setback is correct, I really can’t imagine what else it could be.
If I had to point to anything, it’s usually the shoulder. If it’s just barely tight, that would probably be okay and not dangerous if it’s the shoulder, but if it were something else like the trim length. It could increase pressure a lot.
Well, unless you really need to load those 15, just set them to the side and load another new or good 15 in their place. You can come back to those and work them in your dies to try and figure it out, but I wouldnt reload them. No point in damaging yourself or the weapon over 15 cases.
Good luck
I may can help, I have a 7 SPRC (which is a wildcat that is a 6.5 prc necked up for a 7mm) I got 100 rounds of Lapua 6.5 prc brass brass and necked them up to 7mm and loaded a test group… Everyone I loaded with new brass, would only close with a very stiff bolt. I called the gunsmith that built the rifle and told him about the extra heavy bolt closing. He said “you are using Lapua 6.5 brass aren’t you” He said that he is having trouble with Lagua 6.5 brass being to thick for some custom chambers. I changed to ADG brass and I have had no more problems… So, i would suggest you use a different type of brass. Lupua makes great brass… but some guns can’t shoot the 6.5 that they make… Hope this helps!!