DGA/barrel tightening story

B

Boyd Allen

Active member
I have a 6PPC that is built on a DGA. The first time that I took it to the range, I noticed that the firing pin strike was slightly off center, but since it seemed to shoot OK, I did not get too excited. I thought about having the bolt checked to see if the off "centernedness" was there, and decided that if it was not, I would probably leave well enough alone, since having the threads recut so that they were more concentric to the bolt raceway, on an action that was glued in, with trigger pin holes in the stock, seemed a daunting prospect that I was not sure would show an increase in accuracy. Some time later, I removed the barrel to measure the tenon, carefully cleaned the action and barrel treads, applied an appropriate amount of Pro-Shot Gold to the tenon, and reassembled the barrel with the action... carefully, with my usual generous amount of torque. I didn't give it much thought until I shot it again, and looked at the primer dent. It was in the middle. Have any of you run into this before?
 
IME off-center strikes are the result of cases which fireform off-center, all to one side. I can't imagine anything in the rifle itself being that far out of line :)

Even though I read of it all the time......

I can't imagine it,

al
 
Al,
I have fire formed a fair number of 6PPC cases, from .220 Russian, and never run into this. The fit at the back is fairly good on these chambers.
 
I know......... I just can't imagine a gun being that far out of line. And I've never seen one....and can't imagine how a barrel could tighten up off-center.
al
 
This would have to be something on the shoulder (Tony would call it lint), and the thread fit would have to be really sloppy for the tenon joint to tilt that much.

Did you just come in to this gun?
 
Many moons ago, I had an early '80's vintage BR 6PPC built on a sleeved 700 that dented the primers about .020 off center. The firing pin hole in the bolt face seemed well centered. Wrapping the tenon with one round of teflon tape centered the firing pin indents on the primer. I suspect the reciever face/barrel shank 'flat-to-flat' wasn't quite so 'flat-to-flat' but never ran it down any further.

My.17 Rem. (unaltered factory action) shows the indents about .015 off center. The hole in the bolt face is off by more than that and pin tip is a sloppy fit in the hole. If the pin fit the hole well, the indents would likely be futher off.

FWIW. -Al
 
Jerry,
Yes, it is new to me. Viewed with a bore scope, it looks like the barrel is an unlapped cut rifled barrel, that seems to be a good candidate for a more aggressive copper solvent. Luckily, I have a bottle of Pro-Shot Copper Solvent IV. Even though it requires more aggressive cleaning, it doesn't seem to foul out all that quickly. Perhaps all that internal topography has room for all the junk that it collects. I kind of like the old rifle, and plan to furnish it with a new tube some time this year.
 
Boyd Allen said:
I kind of like the old rifle, and plan to furnish it with a new tube some time this year.
Click to expand...
I love old guns, old cars, faster horses, and old whiskey. But what I am wondering about is how loose is the thread fit. If it allowed enough "cocking" to take the chamber base off center????
 
Compared to my other ppc, it seems to be fine. Perhaps there was some stuff in the lower lug recess that held the bolt off center. I have no idea, but I am glad that for whatever reason the problem resolved itself.
 
I had a winchester model 70 coyote in 22-250 that dented primers way off center. The firing pin was within .005 of center

on the bolt. The chamber was quite large so assumed that cases were just not forming on center. I replaced the barrel
making it a 6br rem ( not norma). The cases showed very minimal expansion at the web. Firing pin dents were no better.
I made a threaded mandril and it advised me that the action was very poor in alignment. Being one of a kind for me, I
sent it to Greg Tannel. He opened it to rem 1 1/16 x16 and the dents are greatly improved. It also shoots better. Clearly
the problem was in the action.
 
Bob,
You should have sent it to me instead. Evidently when I remove and reinstall a barrel, there is some magic involved.;)
 
Hi German,
Yes it would be, but since I no longer seem to have a problem, I think that that will have to wait till I am about to have a new barrel chambered. While I had it apart, I took a toothbrush to the action threads, cleaning them up thoroughly, as well as the tenon threads, and the lug recess area. Previously when it locked up on a tight case, the feel had been a bit funny, but now it feels more standard. Perhaps in the cleaning I dislodged something that had been adversely affecting alignment.

Recently, my Hart rest got a little wet, and when I got home, I took it apart for a good cleaning and lubricating, to make sure that no rust got started. When I dd I noticed that the rear leg height adjustment screw seemed to be in some sort of a bind. Thinking that whatever was in the threaded hole would easily come out, I tried various methods, including squirting Kroil down the hole, and poking pieces of patch through, from end to end. What I eventually had to do was to take an old bore brush, put a kink in it and brush out the threads. From that I learned that if a piece of sand gets wedged in a length of internal thread, that it may not just fall out when the parts are disassembled.
 
You must log in or register to reply here.
Back
Top