While my rifle is in pieces, awaiting its new stock and barrel, I decided to check the locking lug contact. Six of the nine were contacting. 30 minutes and many lapping compound changes later..........contact on all nine. The original six are about 95%, with the last three being about 70% right now. I know this will affect my headspace if I wasn't swapping barrels, but being as how the belt is what controls the headspace, wouldn't this tiny amount of material be negligible?
Lapping Weatherby lugs
- Thread starter ffwd
- Start date
Even headspacing on the belt this would affect headspace, as your moving the bolt back from the barrel, effectively lengthening the chamber.
Whether the amount would be a problem or not is another question, there is some tolerance for headspace, so it might not matter anyway. However headspacing on the rim, belt or shoulder doesn't make any difference.
As you said you are changing barrels, you will have to set up the headspace anyway, so doing the lapping first was a good idea.
That is my understanding of headspace anyway, there are more knowledgable people who can either confirm or correct me.
Whether the amount would be a problem or not is another question, there is some tolerance for headspace, so it might not matter anyway. However headspacing on the rim, belt or shoulder doesn't make any difference.
As you said you are changing barrels, you will have to set up the headspace anyway, so doing the lapping first was a good idea.
That is my understanding of headspace anyway, there are more knowledgable people who can either confirm or correct me.
Can you elaborate on causing problems? I have only lapped one bolt ever, and didn't shoot it before doing so, was putting a new barrel on, so I have no idea on the effects. Inquiring minds would like to know...
The major problem I see on lapped lugs is an angled seat and lugs. The other potential problem is misalignment caused by poor technique. I have a model 70 in the shop which features locking lugs and seats which look like those of an Enfield from overzealous lapping.
Quite often, the appearance of uneven contact on lugs is deceptive and is caused by deflection of the bolt by the sear/ striker contact. Having said this, I doubt you have done any real harm. If you are getting a new barrel anyway, the barrel will be chambered according to the dimensions of the action as it presently is so it won't matter.
Al though lug lapping was SOP back in the day, it is less so now. Still, it can be beneficial if done well. I do know that I would much rather lap the lugs on a MKV than to re-machine the lugs and seats! Regards, Bill
Quite often, the appearance of uneven contact on lugs is deceptive and is caused by deflection of the bolt by the sear/ striker contact. Having said this, I doubt you have done any real harm. If you are getting a new barrel anyway, the barrel will be chambered according to the dimensions of the action as it presently is so it won't matter.
Al though lug lapping was SOP back in the day, it is less so now. Still, it can be beneficial if done well. I do know that I would much rather lap the lugs on a MKV than to re-machine the lugs and seats! Regards, Bill
