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3/29/2015 11:44:21 PM EDT
I recently purchased my first AR-15, a Daniel Defense DDM4. A friend of mine insists I should lap the barrel. Is this really necessary? To be honest, I'm a little apprehensive about messing with a barrel on such an expensive rifle.
3/30/2015 12:03:27 AM EDT
[#1]
Why is he wanting you to lap the barrel?
3/30/2015 12:11:08 AM EDT
[#2]
He claims it will increase accuracy. I have never heard of anyone lapping a barrel in an AR so I figured I better do some research. I will probably pass on the lapping but was curious none the less.
3/30/2015 1:28:22 AM EDT
[#3]
Yeah...skip that bullshit. For a battle rifle, it's not gonna make any appreciable difference.
3/30/2015 1:32:43 AM EDT
[#4]
Quote History
Quoted:
Yeah...skip that bullshit. For a battle rifle, it's not gonna make any appreciable difference.
View Quote

Oh, it will make an appreciable difference alright.

Assuming you're using the fire lapping kit I'm thinking of, you'll destroy it if you follow the directions.
3/30/2015 11:43:02 AM EDT
[#5]
I don't think I've ever heard about someone lapping a chrome lined barrel. Don't do it!
3/30/2015 11:53:22 AM EDT
[#6]
did your friend attend WECSOGS and learned just enough technical wording to be dangerous and thinks he knows what he is talking about ?
3/30/2015 12:06:03 PM EDT
[#7]
AFAIK fire lapping should only be done on precision barrels that aren't chrome lined only at the manufacturer's suggestion, and even then the practice is debatable.

Dingbats that fire lap handguns and AR barrels are simply accelerating their wear and decreasing their barrel life.
3/30/2015 9:06:25 PM EDT
[#8]
Thanks. I hadn't heard of anyone lapping an AR or hunting rifles for that matter. I will stick to my original thought on this and pass on the lapping.
3/31/2015 1:33:22 PM EDT
[#9]
In my opinion, the only people that should be lapping barrels are barrel manufacturers....
3/31/2015 10:35:27 PM EDT
[#10]
Quote History
Quoted:
did your friend attend WECSOGS and learned just enough technical wording to be dangerous and thinks he knows what he is talking about ?
View Quote


WECSOG certification is the best.

Better get a Dremel.
4/1/2015 10:55:29 AM EDT
[#11]
The point of lapping a barrel is to remove tool marks or roughness that may have occurred during the boring and/or rifling process. Your DD barrel appears to be forged so no boring or rifling was performed.

It also appears to be a chrome lined. The very nature of the plating process would tend to smooth out any roughness that might exist.

There are legitimate reasons to lap an AR barrel, but none for your barrel.
4/1/2015 3:45:08 PM EDT
[#12]
Quote History
Quoted:
Thanks. I hadn't heard of anyone lapping an AR or hunting rifles for that matter. I will stick to my original thought on this and pass on the lapping.
View Quote


JP lead laps their AR barrels. Kidd laps their 10/22 barrels as well. There are lots of lapped barrels out their but they are usually not run of the mill standard barrels.
4/1/2015 7:50:16 PM EDT
[#13]
Just shoot it.
4/1/2015 8:03:51 PM EDT
[#14]
Your friend might not know what lapping is or his meaning of "lapping" may be different from yours and many others.

As some have mentioned lapping a barrel is something usually performed by the barrel manufacturer.   However some take it to mean lapping the barrel crown.   Also some could mean lapping the receiver vs the barrel to help ensure the receiver is square to the barrel.    The last two "lapping" is something many AR builders do with their barrels/receivers.
4/2/2015 10:42:09 PM EDT
[#15]
Quoted:
I recently purchased my first AR-15, a Daniel Defense DDM4. A friend of mine insists I should lap the barrel. Is this really necessary? To be honest, I'm a little apprehensive about messing with a barrel on such an expensive rifle.
View Quote

Do not take any gunsmithing advice from this friend.
As long as he is buying the beer, an occasional nod is OK.
4/3/2015 9:42:38 AM EDT
[#16]
Lapping a chrome lined barrel I don't think would do anything. (ETA: if anything would damage the chrome)

you can fire lap (shoot abrasive bullets)for non lined barrels and it may help for match rifle type accuracy (not for combat accuracy).
here's one test: http://www.accuratereloading.com/fire.html

When I bought my LaRue OBR I purchased some lapping rounds (loaded rounds, I forget who makes them).  I figured it may help smooth out any machine marks, and would be unlikely to hurt anything.  Not sure if it makes a difference (didn't do before and after groups).

Actually, the ammo was from David Tubb: link

ETA: not recommending you use them to lap.  As per first sentence no lapping needed or desired in chrome lined barrels.  just pointing out that it isn't a completely idiotic concept (can help in stainless, match barrels).
4/9/2015 2:03:25 PM EDT
[#17]
Tell him "you first"...
4/9/2015 2:05:27 PM EDT
[#18]
Quote History
Quoted:
Lapping a chrome lined barrel I don't think would do anything.

you can fire lap (shoot abrasive bullets)for non lined barrels and it may help for match rifle type accuracy (not for combat accuracy).
here's one test: http://www.accuratereloading.com/fire.html

When I bought my LaRue OBR I purchased some lapping rounds (loaded rounds, I forget who makes them).  I figured it may help smooth out any machine marks, and would be unlikely to hurt anything.  Not sure if it makes a difference (didn't do before and after groups).

Actually, the ammo was from David Tubb: link

ETA: not recommending you use them to lap.  As per first sentence no lapping needed or desired in chrome lined barrels.  just pointing out that it isn't a completely idiotic concept (can help in stainless, match barrels).
View Quote


It would destroy the chrome lining.
4/10/2015 7:09:31 AM EDT
[#19]
Quote History
Quoted:


It would destroy the chrome lining.
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
Lapping a chrome lined barrel I don't think would do anything.

you can fire lap (shoot abrasive bullets)for non lined barrels and it may help for match rifle type accuracy (not for combat accuracy).
here's one test: http://www.accuratereloading.com/fire.html

When I bought my LaRue OBR I purchased some lapping rounds (loaded rounds, I forget who makes them).  I figured it may help smooth out any machine marks, and would be unlikely to hurt anything.  Not sure if it makes a difference (didn't do before and after groups).

Actually, the ammo was from David Tubb: link

ETA: not recommending you use them to lap.  As per first sentence no lapping needed or desired in chrome lined barrels.  just pointing out that it isn't a completely idiotic concept (can help in stainless, match barrels).


It would destroy the chrome lining.



You are right, I'll edit.  Mentioned at end lapping chrome not "desired", but I agree that if anything it would do damage rather than just "not help"
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