During my load development I've noticed that regardless the load/charge/OAL my primers crater. Is there any other advantage to having ones bolt bushed other than to eliminate cratering? Would that keep primer pockets tighter over multiple firings? Greg does this service for a very reasonable price of something like $80. I just can't justify the $80 if all it does is make my spent primers pretty.
If as you state you are experiencing primers flowing into the firing pin hole no matter what load/charge you are using you have excessive clearance between the firing pin tip and the firing pin hole in the bolt. Bushing the bolt is one solution, however if you are looking for a less costly fix you might try replacing the firing pin. I would check the diameter of your existing firing pin tip and that of the new firing pin. If the new firing pin's tip is bigger and thus a better fit in the firing pin hole in your bolt your problem may be solved. Before having your gunsmith bush your bolt you might inquire what he charges to replace just the firing pin tip if a new firing pin doesn't solve the problem. Either fix will get the job done, though cost for either may be the same. Hope you find these suggestions useful in solving your problem.
My 223AI was sloppy, cratering even mid-range loads. It finally punched through a primer, so I had it bushed by Gre-Tan. End of problem. I built a 6.5x47L on a 700 and it was sloppy too, he fixed that one as well. Money well spent if you are constantly worried about primer piercing. I often don't wear eye-protection when hunting, so it was also a peace of mind thing for me.
When the primer cup is extruding into the hole, it all comes down to the area of the hole, along with some other factors such as pin tip shape, striker mass, spring preload, spring rate. If a hole is on the large side, a firing pin which fits the hole will probably not help much and may, in fact, make things worse by weakening the cup in a more vulnerable area. The post 64 Model 70's, for whatever the reason, have larger firing pin tips and larger holes in the bolt face and cratering and blanking are common issues. It used to be that my first move was to install a heavier spring and this occasionally worked. If the problem persisted, I would re-shape and polish the firing pin tip and reduce the protrusion. With all three changes about 50% appeared to be cured but sometimes, they got worse. Someone, and I don't recall who it was, pointed out to me that the heavier spring might actually cause the striker to bounce back a bit and leave the primer cup unsupported. Now, if I have a rifle which is blanking primers, I bush the bolt and turn down the firing pin tip; the cure rate is 100%. The exception might be where there is an obvious contributing factor, such as the shape of the firing pin tip. In this case, I'll re-shape the tip first. Small rifle primer are more commonly blanked than are LR primers. This is why so many 6BR's, in Model 70's and Model 700's, have to be bushed. GD
I recently re-barreled a 700 with the same issue. I ended up bushing that one since it was a 30-338 and the owner tended to want to hot-rod it a bit. GD
My RAR Compact pierces primers with warm loads occasionally for this reason. Even with mild loads the primer craters considerably. It's really annoying. Will need to have it addressed.
Aren't bolt bushing and firing pin bushing two totally different operations? Bolt bushing tightens bolt in receiver raceway.
Last edited by foogle; 05/13/16.
"We are building a dictatorship of relativism which recoqnizes nothing as definitive and whose ultimate goal consists solely of ones own self ego and desires."Cardinal Rathzinger
My RAR Compact pierces primers with warm loads occasionally for this reason. Even with mild loads the primer craters considerably. It's really annoying. Will need to have it addressed.
Mine does the same. Wonder if Greg will work on these?
