To bush or not to bush???????

[338 Mollett]

Once you go bush, you'll never go back

I like bush!

 

[338 Mollett]

Sorry ,my post count was on 666 and there is a match tomorrow.I had to post sumpin!

 

[gotcha]

I shoot for something like the 3rd pin in the picture. But I have never experimented with shape, never found a need to.

Thanks for the input Alex .............................. Obviously, I have experimented with SHAPE (Savage 110 action) and solved a cratering & pierced primer (hotter loads) problem. Glad to see you picked a F/P shape more in keeping with Tony Boyer's advice.

 

[snert]

I like bush!

I prefer bush free, but then never pierced a primer so....

 

[msinc]

I prefer bush free, but then never pierced a primer so....

"Bush free"?????? My man, I can assure you there is no such thing!!!!! Whether you ever pierced any primers or not....it will cost you!!!!!

 

[eddief]

The primer flow you are seeing is from the chamfer around your boltface firing pin hole. Don't worry you didn't cause this, it came from remington like that. Have it bushed and be done with it.

 

[BoydAllen]

First of all, if you are not piercing primers what you have is more of an aesthetic problem. Secondly, you can get a crater from the combination of a soft cup, a light spring, and the shape of the pin tip. It can be a combination of factors. The pressure in the primer pocked during firing can back the pin up a bit. If this moves the full diameter of the pin below the edge of the hole that creates a space for the primer cup to be moved into. On the 6 1/2 primers...they were not designed for any more pressure than a .22 Hornet. When Remington came out with the .222 they found that the 6 1/2s were not up to the pressure of the new cartridge, which was the first small primer high pressure round, so they came out with a tougher primer, the 7 1/2. It has a thicker cup. After that pretty much all of the small rifle primers that I can think of had thick enough cups for the higher pressure cartridges. I would guess that the reason that Remington still makes the 6 1/2s is that there are some older hammer type rifles out there in Hornet that do not have as much striker energy as modern rifles, and with a case that small, a milder primer works better. If it were my rifle, given the chamfer shown on the edge of the firing pin hole, as the others have suggested, I would send it off to Greg Tannel to be bushed. On the firing pint tip shape, years ago a very experienced shooter told met that the correct shape is not a hemisphere but rather more flattened in the center. That a proper shape has two radii, a smaller one at the edge and a larger one in the center.

Decades ago, I did a severe overload in a rifle that had a very sharp edged striker hole, a very heavy firing pin that fit the hole well, and a very strong striker spring. Although the primer fell out of the case when I opened the bolt, it had no crater.

As others have said, based on the edges of the fired primers in your initial picture, the load was not a hot one.

 

[msinc]

I understand, I am going to first try the more favorable looking firing pin that I have and see what if anything different happens...if it stops the cratering then I might just stop at that. The three cases have three different primers and they all do the same thing so I don't know if swapping out primers will change too much.
I like the whole bushing idea and I will more than likely bush the thing if the striker swap doesn't completely fix the problem. Thanks for all the replies so far. I will keep you guys posted as to what happens...just haven't had time to work on the rifle lately.

 

[rogn]

I have to ask- from the looks of your fired primers they appear to have had the striker pushed back to some degree. Have you checked the strength of the firing pin spring. They can take a set over time and loose strength. This may or maynot result in misfires, less likely with soft primers. But since there is a matter of pressure and the spring does support the firing pin, a weaker spring can allow the chamber pressure to push the pin back and accentuate the apparent "cratering".
Urban legend has it that Remi bolts are finished up using the firing pin hole as a "center", hence the champfer.

 

[carlsbad]

I agree with rogn that the pressure pushes the firing pin back up. However, making the spring stronger makes it harder to cock etc. If your spring is adequate for reliable ignition, I wouldn't change it...but then you already know I always recommend bushing.

Second, although it is conceivable a new spring might reduce cratering, I would not expect it to stop it.
--Jerry

 

[msinc]

I have to ask- from the looks of your fired primers they appear to have had the striker pushed back to some degree. Have you checked the strength of the firing pin spring. They can take a set over time and loose strength. This may or maynot result in misfires, less likely with soft primers. But since there is a matter of pressure and the spring does support the firing pin, a weaker spring can allow the chamber pressure to push the pin back and accentuate the apparent "cratering".
Urban legend has it that Remi bolts are finished up using the firing pin hole as a "center", hence the champfer.

This rifle has a Wolf spring in the bolt and as far as I know it is stronger than the factory one. That of course doesn't mean it actually is...I don't have a spring tester. Never have had any misfires. I can tell you this...if Remington used this ones firing pin hole for a center, they severely missed the boat because I am in the process of bushing this thing right now and the best I can dial up this bolt is .010"

Thanks again for all the replies on this thread fellas....when I get this thing finished later today I will post a follow up with the results and some photos.

 

[msinc]

So, I got the bushing made and installed yesterday evening. I finally got time to attempt this. This morning I bored and faced it and ground the firing pin to work. I used the more favorable looking one of the three I had. Put this thing together and tried it out......looks like success so far!!!! Here are the same three different brands of primers used before in the beginning of this thread I shot today. No more bolt click and no more cratering. Also a photo of the face of the finished bolt.....not as pretty as Carlsbad's, but he's not as severe a hillbilly as me either!!!! Thanks again to everyone who helped out with this issue. I musta did somethin' right...the striker assembly didn't blow out the back of my skull....

 

[dkhunt14]

So, I got the bushing made and installed yesterday evening. I finally got time to attempt this. This morning I bored and faced it and ground the firing pin to work. I used the more favorable looking one of the three I had. Put this thing together and tried it out......looks like success so far!!!! Here are the same three different brands of primers used before in the beginning of this thread I shot today. No more bolt click and no more cratering. Also a photo of the face of the finished bolt.....not as pretty as Carlsbad's, but he's not as severe a hillbilly as me either!!!! Thanks again to everyone who helped out with this issue. I musta did somethin' right...the striker assembly didn't blow out the back of my skull....

Those primers look way better. Good work. Matt

 

[msinc]

Those primers look way better. Good work. Matt

Thank you sir!!!!