Comparison Sionics, Colt, GMB, and various triggers

[26 Inf]

Spent a couple hours late this afternoon doing some shooting to compare MY accuracy with different barrels and triggers.

I took four rifles out:

1) 16 inch Sionics LW Mid-Length (5.56 1:8) BCM Upper, Centurion Rail, MBT 2S trigger, Leupold Mark AR 1.5x4 Scope (this is my wife's rifle, pretty much shot to zero and a couple rounds every now and again)

Rifles 2 - 4 all used the same Burris MSR .223 3x9 scope. I moved it from rifle to rifle, did not zero because shooting for groups.

2) Colt CCU Upper, Colt Lower, Stock Trigger, (I just put this together, the 10 rounds fired through it are the only rounds it has fired)

3) GMB GM-M8 (16" 5.56 1:8 Mid-Length) MI Rail, Geissele SD-E trigger. (this is the rifle I shoot the most, I built it right after attending my first Greg 'Sully" Sullivan srmorer school)

4. GMB GM-M18 (18" .223 Wylde 1:8 Rifle-Length Stainless Fluted), ALG Rail, ALG ACT,

Shot everything at 100 yards, using a Caldwell Tack Driver rest off a concrete bench. No rear support. Ammo used was PPU, 62gr HPBT, 223 Remington Match. I shot 5 round groups so I would have enough ammunition to get through all the rifles.

My intent was to shoot the uppers on lowers with MBT-1S, MBT-2S, Geissele SD-E, and the 'stock' trigger if the rifle wears one. Problem was the lower with the MBT-1S is for a dedicated 22 upper and, therefore, didn't have a carbine spring and buffer. I had H, H-2 and H-3 buffers in my bag, but no springs. The rifles have A5 extensions, except for the Colt, which didn't dawn on me until later. So some don't have 3 trigger groups.

Sionics LW, ML, 1:8 - MBT-2S group 0.644"; MBT-1S group 1.650"

The Sionics had the best group overall, the MBT-1S shots were the first I fired with the MBT-1S, I had one called and one other flyer with this group. These were also the only groups fired at 4 power.

Colt CCU - Stock Colt Trigger: 1.544"; MBT-1S: 1.135"

As I noted these were the first rounds through this upper. The trigger in the stock Colt lower was gritty, it had two distinct grinds before let off, I had dabbed some ALG Go-Juice on the surfaces using a long Q-tip, but nothing else. The MBT-1S managed to surprise me each time it broke.

18" GMB-M21 - ALG ACT: .970"; MBT-2S: .738"; SD-E: .714"

I was pretty disappointed the 16" Sionics and the 16" GMB-M8 both grouped better than this barrel.

16" GMB-M8 - MBT-1S: 1.065"; MBT-2S: .689"; SD-E: .669"

This is a thoroughly broken in barrel, I knew it shot good, but I was surprised at how well it compared.

Overall, I was really surprised with the Sionics, it grouped better than the others, and as noted was shot at 4x while the others were shot at 9x.

I was happy that there wasn't a marked difference between the MBT-2S and the SDE.

Still going to wait before offering opinion on the MBT-1S.

All in all, a fun way to spend a late afternoon, early evening.

[opngrnd]

Your results with the Sionics LW barrel are what I was expecting when saw it in the line up. They are often a very accurate "sample of one" for people I shoot with, and for myself. I have shot mine with other shooters to include new shooters and easily kept an average under 2" at 100, and usually much better. I'll be testing another LW barrel this week with a 3x9 scope and on a lower with a SSA-E, and I'll be happy if it shoots comparable.

Edit- Thanks for sharing your results.

[controlledpairs2]

Thanks for sharing. Will be looking at sionics

[everready73]

Appreciate the data points. Always nice to see real world data. NIce shooting as well, getting sub minute groups with almost all barrels. I bet the Colt will get a little more accurate once it settle in

My Sionics barrel shoots very well fro a chrome lined barrel as well. They are my go to now. Cheaper than DD and just as accurate, better gas port sizing than the GM barrels i have used at similar price

I know you said you were withholding judgement on the MBT-1S, but did it come with a heavy and light spring? Did you happen to measure the pull weight? There has been some conflicting data on this compared to what they list on their website

[26 Inf]

I know you said you were withholding judgement on the MBT-1S, but did it come with a heavy and light spring? Did you happen to measure the pull weight? There has been some conflicting data on this compared to what they list on their website

No, I didn't. Light spring came installed. I'll see if I can get it done.

The MBT-1S felt much lighter than the Colt trigger, unsure about a feel comparison with the ALG ACT. It is smooth, which actually led me to call a couple shots through out the sampling that I did.

I would actually describe the Colt as grinding rather than gritty, it had two distinct ledges, the last one right before let off (close as I can describe it).

[ssc]

I have had the same result with both of my Sionics LW uppers. They both shoot under 2 inches with my reloads, which are not anything special. Same with cheap 55 grain factory rounds. They consistenly outshoot my BCM ELW uppers, though one BCM is very close.

Cheers, Steve

[26 Inf]

I have had the same result with both of my Sionics LW uppers. They both shoot under 2 inches with my reloads, which are not anything special. Same with cheap 55 grain factory rounds. They consistenly outshoot my BCM ELW uppers, though one BCM is very close.

Cheers, Steve

I was well pleased with the way the 62gr PPU Match shot. Remember, I was using 4 or 9 power and a bag off a concrete bench.

[Pappabear]

Spent a couple hours late this afternoon doing some shooting to compare MY accuracy with different barrels and triggers.

I took four rifles out:

1) 16 inch Sionics LW Mid-Length (5.56 1:8) BCM Upper, Centurion Rail, MBT 2S trigger, Leupold Mark AR 1.5x4 Scope (this is my wife's rifle, pretty much shot to zero and a couple rounds every now and again)

Rifles 2 - 4 all used the same Burris MSR .223 3x9 scope. I moved it from rifle to rifle, did not zero because shooting for groups.

2) Colt CCU Upper, Colt Lower, Stock Trigger, (I just put this together, the 10 rounds fired through it are the only rounds it has fired)

3) GMB GM-M8 (16" 5.56 1:8 Mid-Length) MI Rail, Geissele SD-E trigger. (this is the rifle I shoot the most, I built it right after attending my first Greg 'Sully" Sullivan srmorer school)

4. GMB GM-M18 (18" .223 Wylde 1:8 Rifle-Length Stainless Fluted), ALG Rail, ALG ACT,

Shot everything at 100 yards, using a Caldwell Tack Driver rest off a concrete bench. No rear support. Ammo used was PPU, 62gr HPBT, 223 Remington Match. I shot 5 round groups so I would have enough ammunition to get through all the rifles.

My intent was to shoot the uppers on lowers with MBT-1S, MBT-2S, Geissele SD-E, and the 'stock' trigger if the rifle wears one. Problem was the lower with the MBT-1S is for a dedicated 22 upper and, therefore, didn't have a carbine spring and buffer. I had H, H-2 and H-3 buffers in my bag, but no springs. The rifles have A5 extensions, except for the Colt, which didn't dawn on me until later. So some don't have 3 trigger groups.

Sionics LW, ML, 1:8 - MBT-2S group 0.644"; MBT-1S group 1.650"

The Sionics had the best group overall, the MBT-1S shots were the first I fired with the MBT-1S, I had one called and one other flyer with this group. These were also the only groups fired at 4 power.

Colt CCU - Stock Colt Trigger: 1.544"; MBT-1S: 1.135"

As I noted these were the first rounds through this upper. The trigger in the stock Colt lower was gritty, it had two distinct grinds before let off, I had dabbed some ALG Go-Juice on the surfaces using a long Q-tip, but nothing else. The MBT-1S managed to surprise me each time it broke.

18" GMB-M21 - ALG ACT: .970"; MBT-2S: .738"; SD-E: .714"

I was pretty disappointed the 16" Sionics and the 16" GMB-M8 both grouped better than this barrel.

16" GMB-M8 - MBT-1S: 1.065"; MBT-2S: .689"; SD-E: .669"

This is a thoroughly broken in barrel, I knew it shot good, but I was surprised at how well it compared.

Overall, I was really surprised with the Sionics, it grouped better than the others, and as noted was shot at 4x while the others were shot at 9x.

I was happy that there wasn't a marked difference between the MBT-2S and the SDE.

Still going to wait before offering opinion on the MBT-1S.

All in all, a fun way to spend a late afternoon, early evening.

Very nice shooting and impressive results. 4X and sub moa is most legit. I have several Sionics barrels and all have been good barrels. So many companies make good barrels these days, its encouraging. You can buy a $350 bolt gun with sub Moa guarantee, thats insane, but that doesn't change these results and shooting. Well done.

Its a testament to how far we have come in many ways. Nice write up.

PB

PB