Wile E Coyote
Well-Known Member
I would like to ask a question about replacing a firing pin on a Rem 700.
If I may, A little background first; the rifle is a New Rem 700 VSSF II chambered for .223 that shoots very good groups. the problem is almost everything (ammo) I shoot shows signs of too much pressure; specifically cratered primers. First thru the gun was factory ammo; Rem. 55gn PSP and Hornady 53gn Vmax. total factory ammo thru the gun is 5 boxes/100 rounds.
I reloaded 25 rem cases (full resize w/shoulder bumped .002)with CCI400 primers, H322 (5) 21gn (5)21.5gn (5) 22gn (5) 22.5gn (5) 23gn. the bullet was a Hornady Amax 52gn seated .060 off the rifling. all cases were trimmed to 1.750". Concentricity of the cartridges was less than .001. all the reloaded rounds chambered easily and grouped considerably better than the factory stuff. The heavier loads were well under 1/2 MOA.
However, all 25 cratered. NO other pressure signs. no soot, no flat primers, the cases extract easy, none have split or deformed into the extractor groove. What was unusual (to me anyway) was that the worst cratering was with the lightest load (21gn). the rest seemed about the same.
A few weeks back I took the gun to the smith to have the headspace checked and this was found to be correct. What he did find was the firing pin has a loose fit in the bolt face but still within spec. I didn't think to ask if the pin was thin or if the hole was big or what the measurement of the gap was. He recommended sending it back to Remington because of the age of the rifle. I prefer not to do this because of a couple bad experiences in the past. more on that another time.
In the gunsafe I have a Tubb speedlok S/A replacement pin and spring that I purchased some time ago for a different rifle. just never got around to installing it. tonight curiosity got me and I disassembled the problem bolt and installed the new pin. It has a noticeably tighter fit yet is completely free - no binding. It is however about .015" longer when set in the "fired" position as compared to the old pin.
The question now is, what is the spec for the firing pin to protrude from the bolt face when in the fired position? Other than side clearance and protrusion, are there any other specs that should be looked at?
I'm going to have this "fixed" soon. Either by putting the Tubb pin in the bolt or by having the gunsmith refit or replace the parts. I may also grudgingly send it back to Remington for repair.
One more note; in order to prove that my reloads were good, the same batch was again reloaded and fired from a friends older rem 700. No pressure problems. just didn't group as well but his gun has a few thousand rounds through it. I also reloaded it a third time and fired it through my AR. No pressure problems.
thanks in advance
If I may, A little background first; the rifle is a New Rem 700 VSSF II chambered for .223 that shoots very good groups. the problem is almost everything (ammo) I shoot shows signs of too much pressure; specifically cratered primers. First thru the gun was factory ammo; Rem. 55gn PSP and Hornady 53gn Vmax. total factory ammo thru the gun is 5 boxes/100 rounds.
I reloaded 25 rem cases (full resize w/shoulder bumped .002)with CCI400 primers, H322 (5) 21gn (5)21.5gn (5) 22gn (5) 22.5gn (5) 23gn. the bullet was a Hornady Amax 52gn seated .060 off the rifling. all cases were trimmed to 1.750". Concentricity of the cartridges was less than .001. all the reloaded rounds chambered easily and grouped considerably better than the factory stuff. The heavier loads were well under 1/2 MOA.
However, all 25 cratered. NO other pressure signs. no soot, no flat primers, the cases extract easy, none have split or deformed into the extractor groove. What was unusual (to me anyway) was that the worst cratering was with the lightest load (21gn). the rest seemed about the same.
A few weeks back I took the gun to the smith to have the headspace checked and this was found to be correct. What he did find was the firing pin has a loose fit in the bolt face but still within spec. I didn't think to ask if the pin was thin or if the hole was big or what the measurement of the gap was. He recommended sending it back to Remington because of the age of the rifle. I prefer not to do this because of a couple bad experiences in the past. more on that another time.
In the gunsafe I have a Tubb speedlok S/A replacement pin and spring that I purchased some time ago for a different rifle. just never got around to installing it. tonight curiosity got me and I disassembled the problem bolt and installed the new pin. It has a noticeably tighter fit yet is completely free - no binding. It is however about .015" longer when set in the "fired" position as compared to the old pin.
The question now is, what is the spec for the firing pin to protrude from the bolt face when in the fired position? Other than side clearance and protrusion, are there any other specs that should be looked at?
I'm going to have this "fixed" soon. Either by putting the Tubb pin in the bolt or by having the gunsmith refit or replace the parts. I may also grudgingly send it back to Remington for repair.
One more note; in order to prove that my reloads were good, the same batch was again reloaded and fired from a friends older rem 700. No pressure problems. just didn't group as well but his gun has a few thousand rounds through it. I also reloaded it a third time and fired it through my AR. No pressure problems.
thanks in advance
