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Posted: 9/3/2026 3:20:54 PM EDT
[Last Edit: dana][Edited]
I have a LMT DI 10.5 that due to time restraints has not been shot much more than a mag or two years ago. In about a month I will get to it and test it out. This is as it sits now. Immediate plans are to use a T2 in a Scalorworks, install a MK8 handguard and test it with a Stacey's Mom K I have. Only thing is I have really been wanting an 11.5. My fear is that the 10.5 will just be brutal and gassy with a tradition can on it. Logic tells me to try it out first and find out. But is the 11.5 just so superior that I should just jump in and go for the 11.5? If I went to 11.5 my plan would be Criterion Core with slightly longer MK8 handguard but still T2 and SM K. I would like to use the rifle from 0 yards all the way out to 400. They immediate problem I still need to address is that magnification becomes an issue for me at that range and I still need to sort that out. I also have a Geissele SBR lower with no upper just sitting in the safe. I could always scratch the LMT and find a factory URGI upper for the Geissele. But then I would still want to build the LMT out. I know, tough problems to have, too many options. The LMT was also my first "nice" SBR so I have a little attachment to it. Kind of why I want to get it put together just right. I also have another 10.5 MK18 Mod 0 inspired SBR. So I dont know if the LMT 10.5 will be redundant. |
| I just ditched a 12.5" upper for an 11.5" barrel that I had chopped to 10.3" (Spike's CHF Pencil). It is setup as my HD/Night gun but I would be comfortable taking it to 400. .063 gas tube with a traditional can and it isn't bad for gas, etc. My wife also has a 10.3" setup with a .063 gas port and traditional can. I'd much rather have the slightly shorter setup considering most use cases we could encounter with it. |
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Originally Posted By Dolor: id just run it but that's just me. Seems like a lot of work for 1". 🤷 Not like we're going from 16 -> 11.5. It seems like too much wasted thought. Shoot it, wear it out, and replace it. |
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Originally Posted By dana: I probably is. When i set this rifle up years ago i shot with the stock too short. Also the ta45 has vary long eye relief. If the can you're using has traditional baffles the barrel length won't matter. You'll have to tune an 11.5 same as the 10.5. If you don't mind adjustable things in your gas system the Bootleg BCG is pretty good at tuning. If you don't like adjustable things maybe look into reduced back pressure cans. I used a high pressure can once. Had to tune the hell out of the rifle. Switched to reduced pressure, and I'll never go back. Just my thoughts on your post. You have rad rifle. A MK8 rail would be cool. Put it on, go shoot. |
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Ignore marketing induced fomo and shoot it. Here's a good read on what you can reasonably expect for effective ranges with various ammo. https://www.ar15.com/forums/AR-15/Suppressed-5-56-SBR-Velocity-Tests-41-Factory-Loads-from-10-5-11-5-12-5-and-14-5-ALL-DONE-/16-714088/ |
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Adding 1" of barrel isn't going to change the dynamics of the can you're using. Basically, it's not going to make much of a meaningful difference. I shoot 10.3" more than any other length, with legacy cans like RCs and NT4s; I have no complaints about gas at all. A standard BCG, a .070" gas port, and a Gasbuster does the job for me. |
Practice, the master of all things. - Augustus
IG: @cqbr.kurdt
Want To Buy: Savannah Mk18 RIS II in light blonde/bronze - LMT SOPMOD Gen 1 Tan - Geissele S3G
IG: @cqbr.kurdt
Want To Buy: Savannah Mk18 RIS II in light blonde/bronze - LMT SOPMOD Gen 1 Tan - Geissele S3G
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Nothing wrong with 10.3/5…a lot of bad guys killed with projectiles from a 10.3” (422m was my record…with an EOTech [fortunately not my funeral]). Run it until it keyholes and maybe then go 11.5”. |
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No rules today, sport…just orders.
It’s not about how many people you kill, it’s about how many you save.
No rules today, sport…just orders.
It’s not about how many people you kill, it’s about how many you save.
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I have two 10.5, and one 10.3. They run fine for what I need them to do. And keymod is fine too. Sometimes it's needed. I have a large diameter carbon fiber barrel. MLOK screws dig into the barrel due to a small clearance issue. So it gets keymod. Most people only don't hang a lot of stuff off the hand guard anyway. |
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There is nothing wrong with the rifle you have. There is also nothing wrong with wanting to change things up for the sake of enjoying the hobby. It comes down to budget, desire, and some sort of goofy justfication. I've gotten really good at stretching to find some sort of goofy justification when the budget and desire are there 
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The 1” of extra barrel isn’t going to change the amount of gas you get with a traditional silencer. I would either 1 Put that 11.5” barrel money towards a lower back pressure silencer. 2 Suppressed gas port barrel (of either length) if you can live with it being dedicated with the silencer. |
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Originally Posted By Marksman14: There is nothing wrong with the rifle you have. There is also nothing wrong with wanting to change things up for the sake of enjoying the hobby. It comes down to budget, desire, and some sort of goofy justfication. I've gotten really good at stretching to find some sort of goofy justification when the budget and desire are there I once built an upper because I had a spare crush washer and I told myself that it was already started so now I have to finish it. |
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Originally Posted By hoody2shoez: I once built an upper because I had a spare crush washer and I told myself that it was already started so now I have to finish it. |
I wanted a mission, and for my sins, they gave me one.
No rules today, sport…just orders.
It’s not about how many people you kill, it’s about how many you save.
No rules today, sport…just orders.
It’s not about how many people you kill, it’s about how many you save.
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I'll just say I'm getting close to 50k suppressed through 10.3" barrels and a good bit more unsuppressed, and there's nothing that magically happens when you add 1". I've got 11.5" barrels, and I see no meaningful difference. If I had to pick one, I'd go 10.3" due to the compact size, and because 10.3" has always been insanely reliable for me. For that matter, if anyone has an RC or NT4 where the "full back pressure" can situation is too much, I'll buy it off you for the cost to switch to a flow-style can. They are pretty awful, I agree. Better to sell those low round-count and high back-pressure cans to me ;). |
Practice, the master of all things. - Augustus
IG: @cqbr.kurdt
Want To Buy: Savannah Mk18 RIS II in light blonde/bronze - LMT SOPMOD Gen 1 Tan - Geissele S3G
IG: @cqbr.kurdt
Want To Buy: Savannah Mk18 RIS II in light blonde/bronze - LMT SOPMOD Gen 1 Tan - Geissele S3G
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Nothing wrong with 10.3 or 11.5; however, I think 12.5 is ideal if suppressed as you can get mid length gas. 12.5 midlength DD Turbo K RB with AGB Attached File |
Isaiah 1:18 - "Come now, let us reason together," says the LORD: "though your sins are like scarlet, they shall be as white as snow"
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A 10.5 is not stupid. And your set up is very nice. I built a 10.3" using a Geissele barrel. Added an OCL Polonium and converted to piston using a Superlative Arms piston kit. It is extremely handy and very accurate. I put a Primary Amrs PLXc Nova on it and it is pretty much perfect now. |
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I have a SOLGW 11.5 w/ Saker K for work and have a Midwest Ind. 10.5 for the house/woods/coyotes etc with the same can you've got on there (Turbo K-rb, right??) and I prefer my personal setup. Ive run both through multiple classes without problems. I don't normally hunt deer with it of course but as far as performance goes, the coyotes don't like it and it's killed a couple of deer with no problems (I know I know, I shouldn't shoot deer with it - yeah, yeah). I wouldn't change a thing bout the 10.5 tho - keep on shooting it until the groups spread out, and then reevaluate if need be. No complaints about 10.5 from me. |
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I had the same thoughts, then I took my PSA/fn 10.5 with a red dot out to 500 on steel just for giggles one day. The holdovers get pretty crazy but it is very doable. I now have zero reservations about it. I still ended up building an 11.5 because of seed parts and sales though. |
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| 10.5 isnt stupid or useless. Its going to feel, in practice, very similar to the 11.5. The 11.5 is objectively better in terms of velocity, dwell time, parts wear, etc. Whether or not you want to spend the money making the swap is up to you. When I had a 10.5, I did swap my barrel for an 11.5 and I was happy with it. Ultimately I found my way back to a 12.5 mid as I have condensed down to being a one rifle man. |
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Originally Posted By jhb3rd: I have a SOLGW 11.5 w/ Saker K for work and have a Midwest Ind. 10.5 for the house/woods/coyotes etc with the same can you've got on there (Turbo K-rb, right??) and I prefer my personal setup. Ive run both through multiple classes without problems. I don't normally hunt deer with it of course but as far as performance goes, the coyotes don't like it and it's killed a couple of deer with no problems (I know I know, I shouldn't shoot deer with it - yeah, yeah). I wouldn't change a thing bout the 10.5 tho - keep on shooting it until the groups spread out, and then reevaluate if need be. No complaints about 10.5 from me. Thats a regular pressurt Turbo K. It ended up being perfect for my 14.5. I 100% love that rifle/can combo. I want the smallest lightest steel can i have on the longer 14.5. TK -RB should be even better. I think 14.5 with a small light can is almost perfect for me out here in mostly open area. It is prety short and small except if you are talking inside a house or truck. It also still shoots like a real rifle when you throw it up on rocks, logs or a berm. All that said i am still keeping my SBRs but they are less ideal out here in Montana than when i lived in Atlanta. Out here the short SBR with a RDS fits a little more like a PDW for moving inside or in and out of the truck. But van be streached out past 100yrds. Or at least that is my idea. I will see when i play with them more. This rifle will get my Stacys Mom K. Or atleast that is the plan. |
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Originally Posted By dana: Thats a regular pressurt Turbo K. It ended up being perfect for my 14.5. I 100% love that rifle/can combo. I want the smallest lightest steel can i have on the longer 14.5. TK -RB should be even better. I think 14.5 with a small light can is almost perfect for me out here in mostly open area. It is prety short and small except if you are talking inside a house or truck. It also still shoots like a real rifle when you throw it up on rocks, logs or a berm. All that said i am still keeping my SBRs but they are less ideal out here in Montana than when i lived in Atlanta. Out here the short SBR with a RDS fits a little more like a PDW for moving inside or in and out of the truck. But van be streached out past 100yrds. Or at least that is my idea. I will see when i play with them more. This rifle will get my Stacys Mom K. Or atleast that is the plan. I split the difference between my 10.3" and 14.5" with a 12.5" for the same reasons (balancing manueverability and effective range). The 10.3" is now a 300bo for hd and the 14.5" doesn't get much playtime anymore. |
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Originally Posted By jhb3rd:I don't normally hunt deer with it of course but as far as performance goes, the coyotes don't like it and it's killed a couple of deer with no problems (I know I know, I shouldn't shoot deer with it - yeah, yeah). I wouldn’t make any excuses to the fuds that don’t know any better. That crap goes back to the time when .224 bullets were all varmint bullets. |
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