300 RUM - Pressure Problems
I have sent old Bessie to the gun doctor, still running into some type of pressure or head space problems.
Tried working up loads with RL- 25, Retumbo and Magnum, started off at min loads and every primer is cratered heavy which is an improvement over the flat primers that started growing lips and rims of their own two weeks ago.
I started out with 180 gr Accubonds, and may have had them set a tweed to long two weeks ago, however the last batch I ran were 200 Accubonds O.A.L. 3.600, Fed 215M in a 300 Rem Sendero 26 in bar. all three powders listed above min loads cratered hard. Cant get this out of the starting block.
The smith looked at a sample of fired casings, said it was pressure and not from head space problems although he has not really gotten that far yet , guess when he starts on the action the truth will come out.
I doubt the chamber is bench rest tight however after inspecting some fired rounds I found two sets of chamber marks printed on the cases a quarter to half inch a part a full 360 degrees. After looking at the chamber mouth, unless they have changed manufacturing procedures, looks like to me that someone at the factory either used a reamer on one to many barrels, reversed it or plain stuck it.
If it's not head space , not sure what the next step is, I can't see three different powders running hot on the lot.
Anybody got any suggestions or had similar problems sure could use it.