So, You Still Wanna Lap Your Bolt?

[Punch The Clown]

This bolt lapping business got pretty heated awhile ago, mostly with the M14 guys. Tim's stand was always avoid lapping. I had an Armscorp receiver that the lugs were over 10 thou off from each other. Lapping would have went through the heat treating. Anyway, interesting WRA receiver that maybe fell victim to bolt lapping?

http://forums.thecmp.org/showthread.php?t=153761

[Eli]

I didn't think 8620 could get that soft!

Eli

[ordmm]

Thanks for the link....should be entertaining to follow. Couple of good comments so far:

"I have taken this receiver out of service but i was wandering if it could be repaired at a reasonable cost."

"I would take it to a metal shop and see what can be done."

[jbkf1003]

Holy Cow. Yes it can be repaired, for about $250 - $300 for a new receiver from the trader's board...

Maybe he lapped too much, and had excessive head space? Allowed the bolt to recoil and peen into the receiver? I wonder what his oprod camming area looks like.

[ordmm]

And back in May...
http://forums.thecmp.org/showthread.php?t=137885


So back in July.....

http://forums.thecmp.org/showthread.php?t=141772





This bolt lapping business got pretty heated awhile ago, mostly with the M14 guys. Tim's stand was always avoid lapping. I had an Armscorp receiver that the lugs were over 10 thou off from each other. Lapping would have went through the heat treating. Anyway, interesting WRA receiver that maybe fell victim to bolt lapping?

http://forums.thecmp.org/showthread.php?t=153761

[Old Guard]

And back in May...
http://forums.thecmp.org/showthread.php?t=137885


So back in July.....

http://forums.thecmp.org/showthread.php?t=141772

Ouch, so the heat treating is that thin?>?200 or more stroke with fine Vl compound? Actually I thought by reading it..The ammo was too hot... Vicious recoil??? What?? New to me, my BP 7.62 conversion is noticeably quieter and softer..in a garand.. Just so I understand the rifle double tapped somehow and made the ledge on the [Softer}edge of the primary locking lug????$auto$

[canes7]

Not that I am a fan of lapping but I doubt lapping caused that!

[Roadkingtrax]

Most of the ages-ago match rifle builders, the guys that built the M1 for the punishment of day-to-day shooting did not like Winchester rifles. I can only think this was part of the reason.

http://i223.photobucket.com/albums/dd281/ttraxler/Winchester_Junk.jpg (http://s223.photobucket.com/user/ttraxler/media/Winchester_Junk.jpg.html)

[timshufflin]

That shoulder is caved in, makes me wonder about the throat.

[Jersey Devil]

Crazy stuff right there!!
I try to not lap bolts if the chamber can be reamed. I know some people swear by lapping, but I try to keep it to an absolute minimum if possible.
Speaking of lapping, I need to ask a question about smoothing out a bore with lapping compound. I'll make my own thread on that, though!!
Thanks for posting this PtC.

[Phil McGrath]

Not that I am a fan of lapping but I doubt lapping caused that!

I'm always a day late in this case many days late too the show. I have too agree I doubt that lapping caused this. I looked at the pic's he provided that right side looks pretty chewed on before he even started so I have too wonder how the left looked before he started, then I read that he was using a chromed lined barrel?

I'm not Ripsaw or what ever his new screen name is, but lapping lugs is a personal cross road that each must cross on there own. I picked up a used M1A that had very low mileage really near new with super tight H/S. From the factory it didn't even measure 1.631 on a PTG H/S gage. The bolt lug contact before lapping was L10 and R15, with minimal lapping it was made L20-R25 H/S checked in at this point at a measurable 1.631. From 1.631 to 1.632 it was almost even contact at 50/50, when all was said and done the H/S ended at just under 1.633 the bolt lugs finished Left at 90%+ and the Right at near 60%. I don't think the .002-.003 of lapping took enough skin off of the heat treatment provided both the bolt and the receiver were done too spec .012-.018.

My .02

[Punch The Clown]

I had an Armscorp receiver that headspaced, but onl on the right lug. The left lug was off by .010. Lapping wouldn't have fixed that. That receiver is one of the reasons I'm a fan of Shuff's mag feed conversions.