View Full Version : Inch headspace/locking shoulder question
June 05, 2002, 18:59
I have put together an inch gun with a Enertprise receiver. When I torqued the barrel on it was tight but not as tight as many others. Checking the headspace demensions I found that I needed a .253 locking shoulder. If I were to remove the barrel and peen the shoulder would that change the locking shoulder size? I know the barrel would be tighter if I did. Should I just get a .253 locking shoulder and install it and not worry?
Thanks for any advice.
June 05, 2002, 19:09
did you use a breeching washer?
June 05, 2002, 19:17
I did use a breeching washer. I think it torqued tight enough but I am just not overly confident. Every metric gun I have barreled has been very tight. This inch gun went together easy. How often are the .253 locking shoulders used?
June 05, 2002, 19:37
How much torque did you use? If in the 100 -150 lbs-ft range, you should be just fine.
I cannot think that peening the shoulder would change HS, but the real issue is that torque is really a function of thread engagement. Peening the shoulder may require more torque to overcome the high spots. Why not just use the next sixe breeching washer?
June 05, 2002, 21:13
Peening barrel NOT a good idea!
Could compromise proper barrel alignment and cause other problems down the road. Breeching washer(s) are by far the best way to go. (My opinion):rolleyes:
June 06, 2002, 17:48
I was reluctant to peen the barrel for the reason you described. I may try the locking shoulder in .253 and keep an eye on things. Does anyone know for sure if a different washer will change the headspace?
June 06, 2002, 19:13
A different washer will NOT change the headspace in any significant manner. If you re-install the barrel to TDC, it shouldn't change anything even an iota.
One rotation of the barrel = 1/16" (.0625")
360 degrees in a rotation = .00017" per degree rotation.
So, if you change your timing by 10 degrees, the gun surely will not cycle due to misaligned gas system, your point of impact will be off 5 moa per degree ( see the Barrel Math thread (http://www.falfiles.com/forums/showthread.php?s=&threadid=21880&highlight=math) ) , and you will have only changed your headspace .0017"
Not to worry.
If your gun uses a breeching washer, it is preferable to use the appropriately-sized washer. However, peening the shoulder is a very effective way to "add a little metal to the shoulder." Ask me how I know.
June 06, 2002, 19:15
Breaching washers of varyinbg thicknesses are used to properly hand time the barrel. A thicker breaching washer hand timing the barrel to 10:30 or 11:00 should give you the higher torque preferred but shouldn't change headspace. Where did the barrel hand time with the existing washer? You could use red or green loktite if you don't have the correct breaching washer.
June 06, 2002, 19:55
It did time at 10:30-11:00. It just timed much easier than expected. I am using a receiver wrench and a regular wrench on the barrel flats with a 2' long pipe over the wrench.
Gary- thanks for the info concerning the headspace issue vs. a thicker breeching washer. I will get the .253 and enjoy. Thanks everyone for responding.
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