Red Dot/Holographic Site discussion

[Farva]

If I could redo my sbr/pistol uppers I would certainly have a BCM 11.5 elw-f with KMR somewhere in the mix. My BCM 11.5 BFH barrel is probably one of the stoutest barrels I own.

I agree. My 10.5" rainier barrel is nice also. If I remember correctly you gain 40% more dwell time in an 11.5" vs a 10.5" barrel.

[DutyUse]

I almost mentioned that same stat I believe BCM is quoted as saying when they were pushing the 11.5 over 10.3.

From what I know and read, If your going to shoot it suppressed, then 10.3's gonna be right up your alley. If shooting unsuppressed an 11.5 might be a better option.

[Farva]

I almost mentioned that same stat I believe BCM is quoted as saying when they were pushing the 11.5 over 10.3.

From what I know and read, If your going to shoot it suppressed, then 10.3's gonna be right up your alley. If shooting unsuppressed an 11.5 might be a better option.

I'm no expert but I understood this to be the opposite. I was under the impression an 11.5" works better as a suppressed host compared to a 10.5". I could be wrong though, it's happened before.

[GOST]

I am a serious sucker for accuracy. In a very big way.

Based on my research if given the right optics or whatever I should probably be able to hit at 400 yards with a 12.5 gun.

That said my concept will most likely be to create a load running 65 grain Seirra SBT or some other similar type of hunting load then fine tune it from there. The primary objective though will be a lot more up close... which is part of the reason I am debating going 11.5. Again though, I don't know if it will make that much difference.

10.5 is a consideration though. For sure.

This is the barrel I'm using on my SBR that I'm currently working on:

http://triarcsystems.com/product/12-...fluted-barrel/

One of the reviews I've read reported that he averaged with M193 3080 FPS and 0.67" groups at a 100. I guess I'll see if my experience will be the same.

[SINNER]

Best length for a 5.56 SBR barrel.

[alamo5000]

This is the barrel I'm using on my SBR that I'm currently working on:

http://triarcsystems.com/product/12-...fluted-barrel/

One of the reviews I've read reported that he averaged with M193 3080 FPS and 0.67" groups at a 100. I guess I'll see if my experience will be the same.

I am still open for barrels but the one that I mentioned is the only one that I know of that is cut to fit longer rails and honestly getting answers on actual lengths for rail/barrel combos is a pain in the ass. I understand that they measure officially from the bolt face, but that measurement alone is not enough to make a decision when you are going for a certain look. Once I get the thing built I will be running with a suppressor so to me it sort of matters to some degree.

That said the other company can't be the only people around that get the concept.

[GOST]

The handguard I plan on using on my 12.5" is the Hodge 11.5" Wedge Lock.

[DutyUse]

I'm no expert but I understood this to be the opposite. I was under the impression an 11.5" works better as a suppressed host compared to a 10.5". I could be wrong though, it's happened before.

Now your making me double guess lol. I'll look it up tomorrow, and I'll be the first to admit if I'm wrong.

The handguard I plan on using on my 12.5" is the Hodge 11.5" Wedge Lock.

Those look amazing

[GOST]

I almost mentioned that same stat I believe BCM is quoted as saying when they were pushing the 11.5 over 10.3.

From what I know and read, If your going to shoot it suppressed, then 10.3's gonna be right up your alley. If shooting unsuppressed an 11.5 might be a better option.

I'm no expert but I understood this to be the opposite. I was under the impression an 11.5" works better as a suppressed host compared to a 10.5". I could be wrong though, it's happened before.

Paul Buffoni the owner of BCM has a post on TOS that explains why he prefers an 11.5" rifle. It has to do with dwell time. Dwell time is the time that your gas operated rifle maintains pressure to continue the cycling of the rifle, dwell time primarily exsists from the time the bullet passes the gas port till it exits the barrel. Paul says that a 11.5" has a 40% longer dwell time than a 10.5" and that's why BCM makes 11.5" barrels instead of 10.5". A lack of dwell time can make a rifle finicky. Shooting suppressed increases the dwell time, think of it as the suppressor adding barrel length. An 11.5" should be more reliable than a 10.5" unsuppressed due to dwell time, but there a lot of 10.5" and 10.3" rifles that run great without suppressors.

[Deadwing]

Man, there are so many variables at work i think it'd be difficult to definitively say a 10.5" will run better suppressed than an 11.5 or vice versa. The additional dwell time of the 11.5 allows chamber pressure to drop a bit more before the round is extracted, allowing for more reliable extraction. But increased dwell time is only good to a certain point. Excessive dwell time can effectively over-gas the gun (this is why mid length gas systems are favored on 16" barrels as opposed to carbine length, not to say that a carbine gas system on a 16" barrel can't be made to function reliably). Adding a can to either a 10.5" or 11.5" barrel will likely result in the gun being overgassed, as the back pressure of the suppressor effectively increases the dwell time (although actual dwell time remains the same in each respective barrel, since the bullet still leaves the bore at the same time it would if shot unsuppressed). Specifics of gas port size, how much back pressure a specific can will add, etc. all play a part. The 11.5 has a higher dwell time than a 10.5, so on paper, with the same can and same relatively sized gas port (i.e. the smallest sized gas port for each barrel that would allow reliable function with nato pressure ammo) in both barrels, the 10.5 would probably be less overgassed than the 11.5. That said, both barrel lengths can be run quite reliably suppressed by running an adjustable gas block, and/or different buffer/spring combos. I don't recall the numbers, but i remember reading that the 10.3" barrels Daniel Defense sells to the general public have a larger gas port than the ones they sell to the military, the logic being that the .mil will always run nato pressure ammo (and frequently run suppressed), where John Q. Public will run everything from Tula .223 to quality 5.56x45 nato. With the smaller gas port of the .mil 10.3, the guy running Tula would find his gun undergassed and have cycling issues. Throw a can on that same gun with the same ammo, and it'd probably cycle fine. Conversely, the commercial spec 10.3" DD barrel will cycle fine with all types of ammo (i've found mine runs best with an H2 buffer using nato pressure ammo), but add a can and you'll probably find you need to run a heavier buffer/spring combo to compensate for the extra pressure in the gas system. Now, on the 11.5" barrel, the gas port could probably be made larger to allow the end user to shoot a variety of different pressure ammo, and the increased dwell time wouldn't make the gun as sensitive to extraction issues associated with an over gassed gun.

I'm no expert, and it's been a while since i stayed in a Holiday Inn Express, so please correct me if my thinking is completely wrong.

[GOST]

Very well put Deadwing, good post.

[Slippers]

Don't overlook gas port sizing. Barrel length becomes irrelevant if the port is too big or too small. It should go without saying that Paul Buffoni prefers an 11.5 over a 10.5 when they're correctly gassed.

You wouldn't use the same port size on a 10.5 and 11.5. Watch out for some of the known overgassed barrels like DD and Larue.

[Hmac]

Don't overlook gas port sizing. Barrel length becomes irrelevant if the port is too big or too small. It should go without saying that Paul Buffoni prefers an 11.5 over a 10.5 when they're correctly gassed.

You wouldn't use the same port size on a 10.5 and 11.5. Watch out for some of the known overgassed barrels like DD and Larue.

Both of my SBRs use BCM BFH 11.5 inch barrels and run perfectly with an H2 buffer for XM193 and an H buffer for .223 PCM. The gas ports are .071. This weekend I shot a 2 day carbine course with Larry Vickers and the 11.5 SBR I used ran perfectly.

I don't care for the Aimpoint Micros, I use a PRO with a G33 magnifier. I flip the magnifier down for 25 yards and farther. Larry is inclined to feel that the magnifier is a great tool but is most appropriate only at 50 yards and beyond. Yeah, I took a little shit for using it inside the 50 yard line but didn't rise to the level of being "that guy" in his mind. He is aware that some day his eyes will be as old as mine.

[Farva]

Paul Buffoni the owner of BCM has a post on TOS that explains why he prefers an 11.5" rifle. It has to do with dwell time. Dwell time is the time that your gas operated rifle maintains pressure to continue the cycling of the rifle, dwell time primarily exsists from the time the bullet passes the gas port till it exits the barrel. Paul says that a 11.5" has a 40% longer dwell time than a 10.5" and that's why BCM makes 11.5" barrels instead of 10.5". A lack of dwell time can make a rifle finicky. Shooting suppressed increases the dwell time, think of it as the suppressor adding barrel length. An 11.5" should be more reliable than a 10.5" unsuppressed due to dwell time, but there a lot of 10.5" and 10.3" rifles that run great without suppressors.

Yes, Paul's statement is what I was referring to.

[Former11B]

I have had issues with EOTechs staying zeroed. Had two that needed rezeroing every 90 days or so.

I'll stick with Aimpoints or maybe the new Trijicon MRO if I ever get the urge to buy one