6.5x47l with large firing pin

[Pigdog]

So I shoot a 6.5x47l and a few weeks ago while testing some loads I noticed a few ejector marks on the brass. This prompted some further investigation. Today I pulled out the firing pin and measured it at approx .073 which I believe is the standard size and not the .062 it should be.

My question is let's say for example I'm running a load at max pressure at the moment of 63kpsi with this large firing pin. If I was to get it bushed will this for example drop the pressure to 60k for example?? Ie am I currently running a load at more pressure hence more throat/brass wear than I need to because of this firing pin size?

Im not sure if that's very clear I'm basically trying to understand that if I got my pin bushed my current load could run at less pressure and wear or alternatively I could load more powder for the same chamber pressure I'm
Currently running??

Thanks

 

[KMart]

Very doubtful that it will reduce the pressure. Pressure is pressure and that is what is causing the ejector marks.
What bushing the firing pin will do is stop the cratering you may be seeing in the primer itself. It will also reduce the possibility of a blown primer.

 

[ShootDots]

So I shoot a 6.5x47l and a few weeks ago while testing some loads I noticed a few ejector marks on the brass. This prompted some further investigation. Today I pulled out the firing pin and measured it at approx .073 which I believe is the standard size and not the .062 it should be.

My question is let's say for example I'm running a load at max pressure at the moment of 63kpsi with this large firing pin. If I was to get it bushed will this for example drop the pressure to 60k for example?? Ie am I currently running a load at more pressure hence more throat/brass wear than I need to because of this firing pin size?

Im not sure if that's very clear I'm basically trying to understand that if I got my pin bushed my current load could run at less pressure and wear or alternatively I could load more powder for the same chamber pressure I'm
Currently running??

Thanks

How far are you bumping the shoulders back? When I see pressure signs with what should be "normal" pressure, I find that many times, the culprit is often NOT bumping the shoulders back about 2-3 thousandths. Bumping the shoulders back will allow the brass to absorb some of that pressure before the chamber walls stop the brass expansion. Without bumping the shoulders back, the cases are up against the shoulder walls immediately, not allowing for any case expansion, hence a pressure spike!

 

[Pigdog]

I'm neck sizing only and bumping the shoulders back every 5th or so firing when they get a bit hard to chamber. That was about 2 firings ago.

So if I don't run a max load there is little benefit in bushing the firing pin? I was under the impression it allowed you to load to higher charges.

 

[MagnumManiac]

I'm neck sizing only and bumping the shoulders back every 5th or so firing when they get a bit hard to chamber. That was about 2 firings ago.

So if I don't run a max load there is little benefit in bushing the firing pin? I was under the impression it allowed you to load to higher charges.

No, the firing pin size has no effect on pressure. What you MAY be confusing these dimensions with is the SIZE of the flash hole in the brass, a .062” hole is often used in SR (small rifle primer) brass. Lapua brass has this size, as do other European made SR brass. Not all do though.

Cheers.

 

[Pigdog]

Thanks guys think I will just leave it as is then.

 

[hogpatrol]

You may want to read what has been researched and written about when it comes to neck only sizing. Condensed, it went out of favor as full length sizing proved more consistent.

 

[Dusty Stevens]

^^ and being consistent is the key to accuracy which means doing the exact same thing on every loading. Annealing every once in a while or bumping shoulders back sometimes is not consistent.

 

[Pigdog]

thanks guys I realise that about neck sizing. When I got the gun it came with Wilson neck sizer dies so I have just rolled with that since. I'm not a competition shooter so this system works well enough for me.