Rifling in AR-15 Barrels: Hand-Lapped Barrel versus Budget Barrel

[Molon]

Rifling in AR-15 Barrels

Hand-Lapped Barrel versus Budget Barrel

The first bore-scope view pictured below shows the rifling on a new Ballistic Advantage barrel. Note the distinct tool marks forming “ridges” on the rifling running perpendicular to the direction of bullet travel.









The next bore-scope view shows the rifling of a hand-lapped Krieger barrel. Note the complete lack of tool marks on the rifling. This particular barrel does have approximately 100 rounds fired through it, but this is just what the rifling looks like when you receive your new barrel from Krieger.








The next bore-scope view shows the throat of an unfired Krieger barrel. You can see that the rifling proper (indicated with the red arrow) just ahead of the leade, shows no perpendicular tool marks.









Hand-lapping is a time consuming, labor intensive process. This is another example of what you’re paying for when buying a top-tier barrel.



....

[Kdubya]

A picture is worth a thousand words. And those pictures require a pretty nice borescope. Thanks for sharing!

Now, does this definitively mean anything in terms of accuracy and precision between the two? I realize that is somewhat of a rhetorical question. What I'm actually more interested in finding is the efficacy of using a product like this on a budget barrel.

http://www.davidtubb.com/final-finish-loaded-ammo

It makes some sense in theory that it might work to smooth out the tool marks, but would one actually find that it produced an improvement of groupings. It'd be interesting to see what that Ballistic Advantage barrel would look like under the scope after using the Final Finish product. And also if any appreciable increase, or possibly decrease, in its precision was achieved. Maybe someone on the forum has already tried this? I realize that there is no substitute for a quality barrel, but it would be nice if there were a product that improved a run of the mill factory barrel for such a small investment.

[ColtSeavers]

Which BA barrel is that? 416R .223 wylde or 4150 CMV 5.56?

Will there be a follow up on each barrel's accuracy and precision? I don't see the point of this thread without that.

[Eurodriver]

A hand lapped, cut rifled Krieger is going to outshoot a button rifled BA every time. Is anyone really debating this?

[GH41]

"It makes some sense in theory that it might work to smooth out the tool marks, but would one actually find that it produced an improvement of groupings. It'd be interesting to see what that Ballistic Advantage barrel would look like under the scope after using the Final Finish product. And also if any appreciable increase, or possibly decrease, in its precision was achieved. Maybe someone on the forum has already tried this? I realize that there is no substitute for a quality barrel, but it would be nice if there were a product that improved a run of the mill factory barrel for such a small investment"

If running abrasive bullets through the barrel worked so well every manufacturer would do it! Krieger and others hand lap not only to improve the surface finish but to maintain a consistent bore diameter. The guy doing the lapping can feel tight spots and work them out. Machines and magic bullets don't feel anything.

[Biggy]

This comparison seems kind of apples to oranges in about every way to me.

[jerrysimons]

Thanks Molon
I want to see some Noveske barrels and other regarded precision barrels vs the Kreiger. I assume I am not getting top quality out of budget barrel brands. But let's see some top tier marketed barrels vs true top shelf hand lapped barrels?

[Skyyr]

Ummm, you said here: https://www.m4carbine.net/showthread...336#post893336

FACT: Even the finest double-hand-lapped, stainless steel match-grade barrel is going to have tooling (reamer) marks

Yet you say in this thread:

Note the complete lack of tool marks on the rifling.

Which one is it?


Also, this doesn't seem very objective either. You're comparing a match-grade barrel with 100 rounds down the pipe, which will polish out the tooling marks (which you claimed above that ALL barrels had) and then use that as proof against a brand new budget barrel that is unfired. Why don't you try comparing apples to apples for once? New barrels against new barrels, broke-in barrels against broke-in barrels, etc. This isn't the first time you've done this, and it was pointed out in the linked thread above when you did something similar.

[Molon]

A hand lapped, cut rifled Krieger is going to outshoot a button rifled BA every time. Is anyone really debating this?

Replies in this thread and it's sister thread would indicated that some people are.

[Skyyr]

Replies in this thread and it's sister thread would indicated that some people are.

I have two Krieger barrels. No one is debating their superiority - I'm questioning your failure to adhere to the scientific method in your presentation of claims, as well as flat-out contradictions (as quoted above).