7.5" vs 10.5" barrels for pistol

[IPApilot]

I've exhausted my google foo and cannot find the answers I'm looking for, so if a thread already exists that can help me, please point me to it.

I want to build AR pistol with a Sig brace. I have some questions I hope you guys can help me with.

My instinct for this "pistol" is to go as small and light as possible, so I'm thinking about a 7.5 inch barrel.

Are there any drawbacks with using the 7.5" barrel?

Any inherent problems with the pistol gas system compared to the carbine length?


However, reliability and overall handling are more important than size. Therefore I am wondering if I should go with a 10.5 or 11.5 inch barrel with a carbine gas system would be the smarter way to go?

Any advice would be appreciated.

I already own a couple of Noveske's and a Daniel Defense. So I understand the value of quality parts and manufactures. It looks like it would be really hard to beat the BCM 11.5 uppers with the Key Mode rail.

Thanks in advance.

[VIP3R 237]

Unless its just a fun blaster the 7.5's are too damn short. They are hard to run reliably, are very harsh on parts, and they are too short to handle well even for my short arms, not to mention ballistics suck.

[HardToHandle]

Had a 7.5" and sold it due to aforementioned compromises. It also spit stupid fireballs and concussion, which is fine on the range but it seemed counterproductive for a serious gun.
Recently I purchased a 10.5" LMT upper to give pistols another try. Ballistic options have also improved in the last five years.

For what it is worth, nose heavy pistons may be even more unbalanced in a pistol than in rifles. No ownership experience, just from fondling.

[Hispanic_Hercules]

I owned a 7.5 and 10.5. For me the 10.5 on a pistol tube setup just seems more comfortable. If I was able to go with a stock (illegal in ca) I would def be ok with the 7.5.

[msigette]

If this is going to be a gun you are planning to bet your life on I would go 10in or 11in bcm. I currently have two 11.5 bcm rifles, and with the info i found on this site that was the best option i found for me. Also use the search button at the top and put in 7.5 and it will pull up numerous threads regarding the pros and coins or the 7.5. There are way too many for me to list so that is your best bet to find the info you desire. Good luck with your build and let us know what you choose and why.

[HKGuns]

I went with a 10.3" DD MK18 and after shooting it I am quite pleased with the decision. The concussion difference between 16" and 10" is significant, but tolerable. I can imagine a 7.5" would be even more significant and perhaps approach intolerable.

ETA: this setup has functioned flawlessly shooting my 69 gr SMK hand loads. See my target, using irons, in the pistol thread.

[WaldoOneFive]

I went with a 10.3" DD MK18 and after shooting it I am quite pleased with the decision. The concussion difference between 16" and 10" is significant. I can imagine a 7.5" would be even more significant.

What are you using for a muzzle device? I searched TONS of threads on TONS of websites, and it seems like the majority of folks running 10.3 and 10.5in barrels without a suppressor have a KX3 but it is heavy, A2, or Troy Claymore... but now we have the cheaper version of the KX3, the KAK flash can that I am hearing good things about.. Any recommendations?

[HKGuns]

What are you using for a muzzle device? I searched TONS of threads on TONS of websites, and it seems like the majority of folks running 10.3 and 10.5in barrels without a suppressor have a KX3 but it is heavy, A2, or Troy Claymore... but now we have the cheaper version of the KX3, the KAK flash can that I am hearing good things about.. Any recommendations?

The DD A2 that comes standard on the MK18. I have the BE Meyers on one of my HK rifles and it is VERY good but it is longer than I want on this setup.

[Slvr Surfr]

I went with a 10.5" for my build for all the reasons stated above. So far w/ 5.56 power ammo it's been flawless. Reliability is iffy with 7-9" barrels, unless a adjustable gas block or piston system is used. It just doesn't seem as bullet proof to me as when going with a slightly longer gas system. YMMV.

[DWood]

Like everyone else here, I have a 10.5" SBR and don't have any experience with a 7.5" SBR.

I hope some who have run the 7.5" barrel will chime in here and relay some experience based on actual use.