BRT OPTIMUM Barrels

**vicious_cb** · 01-06-23, 23:40

Originally Posted by Clint

Molon just posted up a review over on TOS of our 16" OPTIMUM HF CL barrel.

An accuracy summary and comparison to other relevant barrels is below.

All are the average of 3 10-round groups using Molon's 55gr Blitzking handloads, except where noted.
ES = Extreme spread, MR = Mean Radius

BRT OPTIMUM HF CL 16" - 1.23" ES .35" MR
Hodge 14.5" - 1.24" ES, N/A MR (only 1 10-round group )
Criterion CORE 16" - 1.12" ES, .39" MR
Colt A2 20" - 1.35" ES, .42" MR ( 6 -10 round groups )
Colt 6920 #1 - 1.39" ES, .44" MR
Colt 6920 #2 - 1.62" ES, .44" MR
Colt M4A1 SOCOM - 0.95" ES, .35" MR

Of special note is the class leading Mean Radius of .35", showing very good consistency of all shots.
Mean Radius includes all shots in the calculation rather than the 2 worst shots used for Extreme Spread.
https://www.ammoman.com/blog/measuri...s-mean-radius/

Seems to be on par with pretty much every other CHF barrel in that weight and profile class, not sure what everyone was bitching about. Something about cobwebs in their barrel or some such non-sense, looks like they shoot fine to me.

**1168** · 01-07-23, 03:18

Originally Posted by AndyLate

Its worth searching the interweb for the "Molon Reference Links" thread on that site, and not just to read the full review.

He pulls no punches, just the facts.

Interesting that Molon's barrel required "thermal fitting" with a BCM upper. I assembled a non-CHF medium profile optimum barrel and a BCM upper last week. No heating or freezing was required, I think the fit was perfect, tight but not too tight to assemble with a little muscle. Yes, that barrel sat around for a while at my house and is out of production now.

Andy

I rebuilt an upper with a BCM upper and BA barrel recently, and needed three trips to the oven and still had to beat its ass.

**JediGuy** · 01-07-23, 06:29

Originally Posted by 1168

… needed three trips to the oven and still had to beat its ass.

Unwed? As info, a Harbor Freight heat gun is a good way to deconflict for those who must share ovens and also like thermal fitting. It’s also good when NC “welcome to the south” pipes freeze in slightly chilly weather.

**Wake27** · 01-07-23, 06:58

One thing to note from Molon’s post though is the ammo. His sample barrel did worse with MK262, it wasn’t terrible but was around 1.5 MOA I think. The above results were with a 55gr hand load. Just more proof that a specific twist rate doesn’t necessarily mean each barrel with that twist will love the same grain.

Sent from my iPhone using Tapatalk Pro

**prepare** · 01-07-23, 07:46

Why didn’t BRT answer Molons questions?

That’s one of things I like most about SOLGW. They’ve been the most transparent and don’t fear transferring knowledge.

**AndyLate** · 01-07-23, 07:49

Originally Posted by 1168

I rebuilt an upper with a BCM upper and BA barrel recently, and needed three trips to the oven and still had to beat its ass.

I have the luck of the Irish. I have only assembled two stripped BCM uppers, both were tight but needed no more than holding the receiver in one hand and tightening the barrel nut with the other (bare hand, no tools) or a couple taps with a rubber mallet.

Originally Posted by prepare

Why didn’t BRT answer Molons questions?

That’s one of things I like most about SOLGW. They’ve been the most transparent and don’t fear transferring knowledge.

Not providing optimum gas port size I somewhat understand. It would be difficult for a consumer to make an informed decision based on gas port size for a non-standard gas length.

Andy

**Clint** · 01-07-23, 09:17

Originally Posted by prepare

Why didn’t BRT answer Molons questions?

That’s one of things I like most about SOLGW. They’ve been the most transparent and don’t fear transferring knowledge.

Originally Posted by Molon

BRT refuses to provide prospective customers with the diameters of the gas ports on the CHF Optimum barrels so that they might make informed purchasing decisions.

We have previously posted why we don't publish all of our gas port sizes, but the answer is a bit more complex than some would like.

We love our informed, expert users and we do provide guidance that our OPTIMUM barrels are tuned for mixed use with and without a suppressor.

This means un-suppressed levels of Gas Drive that are lower than normally found, but not the smallest gas ports that border on failure if conditions aren't perfect.

We test with PMC Bronze as the lowest power ammo that is expected to run reliably.

There shouldn't be any expectation that extra weak / steel case ammo will run with acceptable reliability.

We also provide guidance to use lighter buffers like CAR/H when un-suppressed and recommend swapping to heavier H2/H3 buffers when suppressed for optimal function.

Very few manufacturers provide buffer recommendations for different scenarios, which is what most users want to know anyhow.

We also utilize several proprietary gas system lengths that properly match the barrel length.

Any gas port sizes provided would have no comparative references and leave perspective customers with more questions than answers.

Speaking of comparative references, aside from the published mil-spec sizes for the Mk18, M4, Mk12 and M16, the internet can't seem to agree on what the proper gas port size for any given configuration and use case should be.

One more thing that's not common knowledge is the required port sizes to achieve a target gas drive can vary slightly based on a number of factors.

These factors include the rifling styles, bore dimensions, chamber dimensions, gas block journal diameters and gas port treatment.

An 076 port in one barrel combination may need an 073 port in another combination to cycle identically.

It is the actual cycling performance that matters, not the exact size required to achieve that performance.

Gas port differences of +/- one size from different manufacturers may cycle the same and shouldn't be cause for alarm until confirmed by actual testing.

**prepare** · 01-07-23, 11:53

Originally Posted by Clint

We have previously posted why we don't publish all of our gas port sizes, but the answer is a bit more complex than some would like.

We love our informed, expert users and we do provide guidance that our OPTIMUM barrels are tuned for mixed use with and without a suppressor.

This means un-suppressed levels of Gas Drive that are lower than normally found, but not the smallest gas ports that border on failure if conditions aren't perfect.

We test with PMC Bronze as the lowest power ammo that is expected to run reliably.

There shouldn't be any expectation that extra weak / steel case ammo will run with acceptable reliability.

We also provide guidance to use lighter buffers like CAR/H when un-suppressed and recommend swapping to heavier H2/H3 buffers when suppressed for optimal function.

Very few manufacturers provide buffer recommendations for different scenarios, which is what most users want to know anyhow.

We also utilize several proprietary gas system lengths that properly match the barrel length.

Any gas port sizes provided would have no comparative references and leave perspective customers with more questions than answers.

Speaking of comparative references, aside from the published mil-spec sizes for the Mk18, M4, Mk12 and M16, the internet can't seem to agree on what the proper gas port size for any given configuration and use case should be.

One more thing that's not common knowledge is the required port sizes to achieve a target gas drive can vary slightly based on a number of factors.

These factors include the rifling styles, bore dimensions, chamber dimensions, gas block journal diameters and gas port treatment.

An 076 port in one barrel combination may need an 073 port in another combination to cycle identically.

It is the actual cycling performance that matters, not the exact size required to achieve that performance.

Gas port differences of +/- one size from different manufacturers may cycle the same and shouldn't be cause for alarm until confirmed by actual testing.

Like!

What do you mean by gas port treatment?