BRT OPTIMUM Barrels

[jpmuscle]

Ok

I’d buy a Clinto barrel




Yes


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[JediGuy]

The EXC gas system is OPTIMUM for 13" barrels.

We like to keep within +/- 0.5" of that, so a 12.5" would be close enough.

A "Clinto" configuration is possible using EXC gas and a Midlength FSB on a 12.5" or 13" barrel.

Very, very cool. Appreciate the info.

[Magsz]

So...

Just put together a new upper and brought it to the range to function test it.

Build is as follows:

BRT LW 16 inch barrel and their gas block.
13 inch BCM MCMR Rail.
Lantac Dragon (I needed a muzzle device and a buddy had this)
8.9 ounce LW Bolt carrier (NP3)
Vltor A5H2.

Im pleased but kind of disappointed. I was hoping that the gun would shoot a little bit softer than it does. Im seeing quite a bit of dot movement, particularly a weird push to the right. IF I REALLY bare down on the gun the dot movement is minimized but this thing moves about as much as my Duty gun, a piece of shit bushmaster 16 inch gun with carbine gas. Yes, there is way less recoil but I also attribute that to the lantac as its a pretty good brake.

I tried the rifle with a standard bolt carrier group and the A5H2 and the results were about the same.

Im running the gun on .223 wolf gold at the moment as I have a ton of that stockpiled.

I was SUPER surprised that the gun as it was configured ran wolf steel case .223 as that stuff is seriously under powered.

Anyone have any thoughts on minimizing that dot jump/push? I was thinking of trying an H1 or H0 to match the reciprocal mass of the light weight carrier. (its a toy, its not a serious use rifle so I wanted to try a lightweight carrier).

[opngrnd]

So...

Just put together a new upper and brought it to the range to function test it.

Build is as follows:

BRT LW 16 inch barrel and their gas block.
13 inch BCM MCMR Rail.
Lantac Dragon (I needed a muzzle device and a buddy had this)
8.9 ounce LW Bolt carrier (NP3)
Vltor A5H2.

Im pleased but kind of disappointed. I was hoping that the gun would shoot a little bit softer than it does. Im seeing quite a bit of dot movement, particularly a weird push to the right. IF I REALLY bare down on the gun the dot movement is minimized but this thing moves about as much as my Duty gun, a piece of shit bushmaster 16 inch gun with carbine gas. Yes, there is way less recoil but I also attribute that to the lantac as its a pretty good brake.

I tried the rifle with a standard bolt carrier group and the A5H2 and the results were about the same.

Im running the gun on .223 wolf gold at the moment as I have a ton of that stockpiled.

I was SUPER surprised that the gun as it was configured ran wolf steel case .223 as that stuff is seriously under powered.

Anyone have any thoughts on minimizing that dot jump/push? I was thinking of trying an H1 or H0 to match the reciprocal mass of the light weight carrier. (its a toy, its not a serious use rifle so I wanted to try a lightweight carrier).

I tried a Tubbs spring and that took some dot movement out as well.

[1168]

So...

Just put together a new upper and brought it to the range to function test it.

Build is as follows:

BRT LW 16 inch barrel and their gas block.
13 inch BCM MCMR Rail.
Lantac Dragon (I needed a muzzle device and a buddy had this)
8.9 ounce LW Bolt carrier (NP3)
Vltor A5H2.

Im pleased but kind of disappointed. I was hoping that the gun would shoot a little bit softer than it does. Im seeing quite a bit of dot movement, particularly a weird push to the right. IF I REALLY bare down on the gun the dot movement is minimized but this thing moves about as much as my Duty gun, a piece of shit bushmaster 16 inch gun with carbine gas. Yes, there is way less recoil but I also attribute that to the lantac as its a pretty good brake.

I tried the rifle with a standard bolt carrier group and the A5H2 and the results were about the same.

Im running the gun on .223 wolf gold at the moment as I have a ton of that stockpiled.

I was SUPER surprised that the gun as it was configured ran wolf steel case .223 as that stuff is seriously under powered.

Anyone have any thoughts on minimizing that dot jump/push? I was thinking of trying an H1 or H0 to match the reciprocal mass of the light weight carrier. (its a toy, its not a serious use rifle so I wanted to try a lightweight carrier).

I’m going to make the assumption that since you’re using a light barrel that the total weight of your rifle is fairly light. This of course affects felt recoil. A properly designed gas system will not work any physics defeating miracles. Also, to maximize the recoil reducing effects of your combination of brake, LW carrier and the lighter buffer you are considering, you may need an adjustable gas block. The weird push to the right may be coming from your stance.

You have to realize that BRT has to consider idiots like me that are too lazy to clean my weapon when they spec gas ports. That little bit of fudge factor is probably why its running steel cased ammo. Properly gassed should not be confused with overly light gamer gassing. It has to run when filthy in cold weather.

I tried a Tubbs spring and that took some dot movement out as well.

I tried the Tubbs (an older model; I think they changed the material at some point, reducing its power) in a carbine extension and I had some stoppages. By this point the rifle was absolutely filthy and had sand and water in it, so I can’t blame the gun.

I also had some stoppages with the Sprinco Blue, even after removing the sand with a water hose and adding lube. Honestly, I think using more spring than your gun needs is a recipe for failure. And I think this barrel doesn’t require a super hot spring. But I suspect the Tubbs will be fine in the longer A5 or rifle extension, especially if you treat your rifle reasonably. Its very noticeably stiff in a carbine extension when charging the weapon.

If you look through my round count logs in this thread, you’ll find the stoppages marked by asterisks. Its worth noting that I mainly shoot outdoors in bad weather so I can have the range to myself.

I am currently using a Sprinco Hot White and H2 buffer with no issues. I still haven’t cleaned it (other than the water hose, and punching the bore/ cleaning crown before testing accuracy), and its filthy. It cycles and locks back even with Federal match .223 69gr, and runs properly with M855, also. Interestingly, ejection patterns don’t vary all that much with mixed ammo.

Clint and I have discussed my stoppages and testing via PM, and I am completely satisfied. I have not experienced any stoppages with the rifle’s current configuration.

~2980
+70 P1 62 556, Frontier 68 556
~3050

[Clint]

These are some excellent points, so let's parse through them.

I’m going to make the assumption that since you’re using a light barrel that the total weight of your rifle is fairly light. This of course affects felt recoil. A properly designed gas system will not work any physics defeating miracles.

Its true; a light rifle will tend to move around more than a mid-weight rifle.

Also, to maximize the recoil reducing effects of your combination of brake, LW carrier and the lighter buffer you are considering, you may need an adjustable gas block.

A brake tends to add a little gas drive, while a light weight reciprocating assembly requires less gas drive.

The combination of the two points to a smaller port size.

You have to realize that BRT has to consider idiots like me that are too lazy to clean my weapon when they spec gas ports. That little bit of fudge factor is probably why its running steel cased ammo. Properly gassed should not be confused with overly light gamer gassing. It has to run when filthy in cold weather.

There are many factors to consider and we don't want to sacrifice reliability just to get ultra light recoil.

Again, the standard gassing is setup for full weight reciprocating parts with an A5 buffer.

I also had some stoppages with the Sprinco Blue, even after removing the sand with a water hose and adding lube. Honestly, I think using more spring than your gun needs is a recipe for failure. And I think this barrel doesn’t require a super hot spring. But I suspect the Tubbs will be fine in the longer A5 or rifle extension, especially if you treat your rifle reasonably. Its very noticeably stiff in a carbine extension when charging the weapon.

By all means, hose out the sand first.

Overly strong springs are generally not helpful with our barrels.

Yes, a strong spring can absorb more recoil energy, but then it returns more energy during counter-recoil, producing higher bolt closing speeds, more muzzle dip and bolt bounce.

OPTIMUM gas drive does not provide for gobs of extra energy to work extra power springs with weak ammo.

I am currently using a Sprinco Hot White and H2 buffer with no issues. I still haven’t cleaned it (other than the water hose, and punching the bore/ cleaning crown before testing accuracy), and its filthy. It cycles and locks back even with Federal match .223 69gr, and runs properly with M855, also. Interestingly, ejection patterns don’t vary all that much with mixed ammo.

Clint and I have discussed my stoppages and testing via PM, and I am completely satisfied. I have not experienced any stoppages with the rifle’s current configuration.

The ejection pattern is interesting but also one of the intentional results of our configuration.

OPTIMUM is relatively insensitive to ammo selection.

The ejection angle and cyclic speed with different ammo changes relatively little compared to other configurations like 16" MID or CAR.

This is a good thing, as we'd like any ammo to run nicely and don't always get to choose the loadings ( issued, availablity, stockpile, etc)


Due to proper timing, OPTIMUM is relatively sensitive to changes in reciprocating mass or buffer weight.

This is also a good thing, as we can generally control the buffers and carriers used.

Shorter gas systems show a variable amount of unlocking friction.

With them, lighter buffer unlocks sooner under more friction, so it gets lets impulse to cycle, but needs less due to the lighter weight.

Similarly, a heavier buffer unlocks later under less friction, so it gets more impulse to cycle, but needs more due the higher weight.

This effect is somewhat self defeating when heavier buffers don't slow down the action as much as expected.

With OPTIMUM, the unlocking friction is low and relatively constant, so a lighter buffer cycles faster and a heaver buffer cycles slower, as expected without the variable unlocking friction forces.

Im pleased but kind of disappointed. I was hoping that the gun would shoot a little bit softer than it does. Im seeing quite a bit of dot movement, particularly a weird push to the right. IF I REALLY bare down on the gun the dot movement is minimized but this thing moves about as much as my Duty gun, a piece of shit bushmaster 16 inch gun with carbine gas. Yes, there is way less recoil but I also attribute that to the lantac as its a pretty good brake.

I tried the rifle with a standard bolt carrier group and the A5H2 and the results were about the same.

Im running the gun on .223 wolf gold at the moment as I have a ton of that stockpiled.

I was SUPER surprised that the gun as it was configured ran wolf steel case .223 as that stuff is seriously under powered.

Anyone have any thoughts on minimizing that dot jump/push? I was thinking of trying an H1 or H0 to match the reciprocal mass of the light weight carrier. (its a toy, its not a serious use rifle so I wanted to try a lightweight carrier).

The lightweight reciprocating assembly and aggressive brake need a bit smaller port to run best.

We'd hate for anyone to be disappointed with our barrels.

If you'd like to get a HD port to adjust for the light carrier, we'd be happy to install it into your existing gas block.

[Magsz]

Couple of things guys.

Please, I hope no one here misconstrues my posts as being unhappy with BRT as a company or the products that they provide. I also hope that no one thinks im being unrealistic in my expectations regarding the product. Im not looking for a gamer setup with zero recoil, nor do I expect the barrel to defeat physics. I am simply trying to make the product fit my desires. If ultimately it doesn't then its not a fault of the product or its design.

I am exceptionally pleased with BRT's customer service from A-Z as evidenced by Clint's above offer. Who offers something like that? He is offering to change his product outside of its normal design parameters to cater to the individual desires of a customer. That is pretty neato.

Before we go to extremes. Does anyone have any feedback for me regarding a lighter buffer? Im a simpleton when it comes to physics so a laymans explanation would be appreciated. Im also entertaining ideas for new muzzle devices. Im not married to anything in particular and im always interested in trying new things.

Thanks fellas!

To Clint, thank you.

[ChattanoogaPhil]

I was hoping that the gun would shoot a little bit softer than it does. Im seeing quite a bit of dot movement, particularly a weird push to the right.

Im also entertaining ideas for new muzzle devices. Im not married to anything in particular and im always interested in trying new things.

Surefire ProComp might help mitigate that. Has a port at 3 o'clock but the 9 o'clock position is just a pilot hole. https://www.surefire.com/procomp-556-1-2-28.html

[opngrnd]

I should clarify that the Tubbs spring I'm using is in a Suppressed build. Adding a suppressor definitely gives an extra variable.

[Magsz]

Surefire ProComp might help mitigate that. Has a port at 3 o'clock but the 9 o'clock position is just a pilot hole. https://www.surefire.com/procomp-556-1-2-28.html

10-4! Ive used the suppressor mount muzzle brakes before and had a pro comp a few years ago. Maybe ill give that a whirl on the build to see how it shakes out.

Also, for the above posters wondering about the overall weight of my rifle. Its 7 lbs 3 ounces with red dot and light. Pretty darned nice weight, mostly in part to the barrel profile.