barrel break in

[masan]

Oh yeah? Why ask about it if it doesn't apply?

Boy you really want to make a good impression huh?

Reading comprehension FTW

[Primus Pilum]

"wondering whether FACTORIES drill the gas port before or after chrome lining."

i think we're having a couple conversations simultaneously. sorry it's hard to follow

also, there's not a current problem with a krieger barrel. euro was just wondering if it mattered whether the port was in a land or groove.

Gotcha. Sorry for the confusion.

I don't think it really matters. You are going to get gas port erosion anyway. A SS barrel will typically be shot out before it becomes an issue and even then, an adjustable gas block can deal with it. Trying to time the extension with the gas port seems like more work than it's worth when cambering an AR barrel.

[taliv]

brief update on my barrel test...

at 515 rounds, i decided to clean the chamber, because rounds weren't going in or coming out as smooth and i thought i was getting some carbon and other misc junk building up in the chamber. so i tried to do this without touching the bore, but didn't do such a good job of that. I used a nylon brush with some slip2k carbon killer on it and just stuck it in there til it stopped and twisted it around. i later measured and realized i'd stuck it an inch or two into the bore. then i used a bunch of swabs like shotgun mops to try to clean out the chamber, but they didn't go into the bore where i'd stuck the solvent. oh well.

so I went out today and shot 2 rounds at a target, then threw the chrono on and shot a 10 rounds group at 540 yards. target is a 12" steel plate.
pretty sure i got some solvent affecting the bore because the velocities I got started out low for several rounds, then went back where i expected them.
velocities were
2770
2777
2774
2774
2763
2774
2783
2783
2782
2777
if you just took the whole 10 rounds as a group, that would still be an SD 6 and ES of 20.
if you looked at it as one group with a slightly molested bore by an idiot that doesn't know how far to stick the brush in, that eventually fouls back in and goes back to normal, it looks a LOT tighter. the two groups i chrono'd in the OP averaged 2780 and 2782 fps, so the last 4 shots look like they're right there. guess it took 6+2 rounds to get there after cleaning the chamber.


good news is it's still shooting decent groups. hard to measure 10 round groups on steel by how the 80 layers of paint randomly flake off, but it looks to me like 2.5" x 2.5" and definitely no more than 3.5" by 3.5" edge to edge.

[masan]

I did a break in and started working up some loads for a new Bartlein barrel yesterday. This was the fastest cleanup/break in I have personally had.

I only got copper on one patch

Attachment 38565

Borescoped it today to confirm that I hadn't missed anything and it was clean as can be.

I am still playing around with loads, but I will share velocity/SD/ES when I am done.

[MarshallDodge]

At one time I was a clean freak but have become less and less of one over the years. I have a factory Remington 223 CS barrel and a Sabre Defense 16" SS barrel that shoot great even though I can actually see the copper fouling in the barrel. The Remington takes at least 10 rounds after cleaning before it will start shooting well and stops throwing one shot out of a group.