I have an Aero 20" govt profile barrel.  Considering about pairing it up with a 2.5x10 optic.

Is a govt sufficient enough for shooting with a magnified optic?  Can I expect a lot of thermal shift due to the skinny profile and lack of heat sink?

A govt profile would be nicer to carry around/shoot off hand instead of a MK12 profile.

Not really planning shooting match grade stuff regularly with it until reloading supplies becomes more available.  I know ammo matters more, but I am curious if I can expect groups to open up after a string of shots or significant thermal shifts in a govt profile.

If you already have the barrel I'd say give it a try with good quality ammo and see if you are happy.

The SPR profile is very heavy and I think a lot of the more modern profiles are likely better suited for most applications if you aren't trying to build a clone.

Depends on what you consider precision.  I can shoot about an inch at 100 on a good day, so can a GI barrel with good ammo.

I think its reasonable to assume its possible to achieve sub-2 MOA accuracy with 55gr ball ammo out of a decent barrel.

I am certainly not expecting sub-MOA accuracy out of a govt profile mass production barrel with ball ammo.

Weight is a factor.  But I was hoping for something a bit better than a 16" variant just to give me collection a little more variety.  Ideally, I was looking for a 18" med contour (something in the sub-2lb range given the MK12 profiles are running at 2.5lbs) rifle length gas barrel.  I would be nice to see a hybrid of govt/MK12 contours.  I contacted Larue about their stealth barrels, but haven't heard back and their website sucks if you want specs.

It certainly would make no sense for me to dump $384 on a BCM MK12 SS410 barrel when I plan on mostly shooting ball ammo out of it.  Especially if there is no gain from a MK12 barrel running ball ammo.  Between the high quality and weight is a bit over the top for what I want to use it for.

I read some reviews on the LaRue Stealth barrels.  Read someone that was getting sub MOA groups with M855 and 1.25" groups with M193.

If you're going for head shots only in the Nat'l Trophy Infantry Team (Rattle Battle) match in which you're doubling the sustained rate of fire, that may be harder to do.

I say if it's made well, yes. https://www.ar15.com/forums/Precision-Rifles/-ARFCOM-1-MOA-ALL-DAY-LONG-Challenge-/17-51/?page=31#i112659

They have some sweet cherries, if that's extreme spread.

The most precise FMJ ammo is/was GECO, GP90, and Belgian SS109, which you could expect 0.6 MOA mean radius. Typical ball ammo is 1.0.

Depends on your definition of accuracy.

Also every barrel is different but if you’re lucky to have a good one 2.5-1.5 moa is plenty doable with m193.

Using high quality lower pressure 223 ammo may help.

Scope and trigger are also important.

Depends more on ammo than barrel.

I've never grouped better than 2 MOA with M193, and average 3. Commercial 223, even budget ammo like Wolf Gold, groups better.

Same barrel will group sub MOA with a Mk262 load.

OP, I've taken an Aero upper/BA gov`t profile barrel out to 980 yards with a 3-9 optic on an F-class target. 77gr TMK handloads. If the barrel is a good one it will do well. Best 5 round group at 980 was 1.57 MOA, best 5 round group at 486 was .0.63 MOA. All distance measurements taken with laser range finder and calculations from range buddy app.

ETA: it shoots right at MOA with 55gr SP for under 300yd varmints/plinking, the TMKs take it to another level. POI close enough to similar for short range, rifle is sighted in for long range. 8208XBR, CCI450, LC brass, 2.255 COAL. Need to test a few other batches as I made some changes to my process that should enable greater precision. Ignore the dates, these were fired on the same day and I was just learning how to use the app and figuring out my actual dope at long range. Would love to put a better barrel on but really hesitant to change a single thing after these results. The visible holes on target are from a Rem 700 5r in .308, tough to pick out the .224 holes with that backer.

486:
Attached File


980: two rounds are nearly stacked making it difficult to see all 5 impacts
Attached File

I consider the trigger and optic to be decent, since it was mentioned.

Vortex Viper PST 2.5-10x32 FFP
Geisselle G2S Trigger

That'll do well out to further than max effective range. FWIW targets above were shot with an ALG ACT and 3-9x40 VX-R., obviously no breeze to get on target at 980 first try simply dialing in to Strelok mil predictions. I was very happy with how close Strelok was to correct dope after punching in bullet specs and chrono velocity, had sighted in at 200 previously a different day before stepping to 486 and then 980.

If you get a good barrel it will be plenty capable out to quite a ways. How far are you trying to push it?

That is very impressive considering most people would say 2-stage triggers would be advantageous for long range and your here knocking out impressive groups on a $60 single stage trigger.

Honestly, really no more than 500.  Its difficult to get long ranges in this area.

Have you shot any factory 5.56?  Any thermal shifts towards the end of a fire cycle?

My biggest concern is what happens when the barrel heats up.  That is where the thicker contours would appear more beneficial.

I'd like to build up some MK262 similar loads once reloading supplies start to come back, but I have no idea when that is coming especially in the currently climate.

Yeah, this one deserves a better trigger, eventually it will get an MBT-2S but for now it can go on another lower if I really needed a better trigger. I haven't fired any great deal of factory 5.56 through or groups but the standard xm193 and PMC Bronze produced acceptable results during break in. Not as good as my 55gr bulk handloads but not awful. With regards to thermal shift, can't say I have stressed it enough to notice but it does live with a can hanging off of it. Mostly 5 and 10 shot groups, nothing crazy. I use heavier barrels and carbines for that type of stuff,

You'll absolutely be good out to 500. Black Hills Mk262 would be a great factory choice if you can get it until supplies come back around.