All purpose "Help me build my AR" thread.

[MPMalloy]

If anyone's interested - the official Army PEO Soldier guide to spray painting your M-16/M-4. Also works for AR-15s. Although the part about taping or otherwise covering the barrel and gas block might be a challenge for rifles with free-float handguards, unless you remove the handguard.

https://www.peosoldier.army.mil/docs/bl ... ing101.pdf

Thank You Lang!!!

Really, thanks a lot for this!

[Langenator]

Anyone know the longest free float handguard that will fit on a 16" barrel with mid-length gas? My tape measure says about 9.5". Anyone here ever tried a build like that?

Branch option question: if you take an A-frame front sight/gas block and chop the sight part off, will it fit under a normal free float guard?

[boskone]

Branch option question: if you take an A-frame front sight/gas block and chop the sight part off, will it fit under a normal free float guard?

It should, I did that with one of mine. Had to cut the sling swivel off too, though the swivel stud and bayonet lug fit underneath just fine.

[williaty]

Can an AR-15 upper be built chambered in something that would meet the following regulation?

All straight-walled cartridge calibers from a minimum of .357 to a maximum of .50.

[dallas]

Can an AR-15 upper be built chambered in something that would meet the following regulation?

All straight-walled cartridge calibers from a minimum of .357 to a maximum of .50.

Yes. 350 Legend, 450 Beowulf and 50 Beowulf fit the criteria.

[boskone]

Can an AR-15 upper be built chambered in something that would meet the following regulation?

All straight-walled cartridge calibers from a minimum of .357 to a maximum of .50.

I assume you don't mean all at once, though that would be a pretty interesting upper.

Offhand, .350 Legend (which is pretty much brand new, actually .357 caliber), .450 Bushmaster (kinda new), and .50 Beowulf (can't remember if it's still proprietary or not).

I believe .350 Legend's performance is comparable to ye olde .30-30, and .450 Bushmaster around .45-70.

Not sure about Beowulf, or even if it's a decent hunting cartridge. By the numbers, seems like it should be at least usable.

[williaty]

After another day of reading, that's pretty much the list everyone is talking about:

.350 Legend
.450 Bushmaster
.500 Beowulf

I'm trying to figure out if there's really a meaningful difference between them to a noob like me. Looks like they're all going to be better than the 20ga slug I'd otherwise use (and cheaper too!). Looks like they all can be finnicky to run in an AR if everything isn't just so. Might come down to which upper is cheapest.

[williaty]

Hmm.. maybe not. Just found a good numbers-based analysis of the 3 calibers. They're pretty similar in terms of killing power (though with the .350 L at the low end of the pack) but the recoil of the .350 L is way, way lower than the other two. That's a big deal honestly.

[PistolPete]

After another day of reading, that's pretty much the list everyone is talking about:

.350 Legend
.450 Bushmaster
.500 Beowulf

I'm trying to figure out if there's really a meaningful difference between them to a noob like me. Looks like they're all going to be better than the 20ga slug I'd otherwise use (and cheaper too!). Looks like they all can be finnicky to run in an AR if everything isn't just so. Might come down to which upper is cheapest.

I'd say 450 Bushmaster has the most support. Whether 350 Legend sticks around or not remains to be seen, it's pretty darn new. 50 Beowulf has been around the longest, but doesn't have a bunch of companies making parts for it and the ammo is pricey. You can find uppers in the generic 12.7x42, it's the same as 50 Beowulf without paying Alexander Arms royalties.

The sticky wicket with 350 legend is it uses 9mm (.355") bullets instead of .357 bullets, so there are very few choices that hold up to the velocity for hunting. Factory offerings are all you've got.

That said, any of them will do the job. I've got a 10" 50 Beowfulf AR pistol I plan to use for handgun deer season in my state. It should do the job.

[williaty]

The sticky wicket with 350 legend is it uses 9mm (.355") bullets instead of .357 bullets, so there are very few choices that hold up to the velocity for hunting.

I've been hitting the research pretty hard. Seems like companies are loading both .355" and .357" bullets into their .350 Legend cartridges. The heavier ones are getting some good reviews for hunting. You're right, though, it's awfully early to see if it's a flash in the pan or not. That being said, the cost per round is like half or less of .450BM and waaaay less than .500Beo. Since this would be a deer-season-only caliber, it's not crazy to think about stocking up on enough cartridges to last me the rest of my life if I'm only using a small number per year.

[boskone]

The sticky wicket with 350 legend is it uses 9mm (.355") bullets instead of .357 bullets, so there are very few choices that hold up to the velocity for hunting.

I've been hitting the research pretty hard. Seems like companies are loading both .355" and .357" bullets into their .350 Legend cartridges. The heavier ones are getting some good reviews for hunting. You're right, though, it's awfully early to see if it's a flash in the pan or not. That being said, the cost per round is like half or less of .450BM and waaaay less than .500Beo. Since this would be a deer-season-only caliber, it's not crazy to think about stocking up on enough cartridges to last me the rest of my life if I'm only using a small number per year.

Do you reload? Might do the math on a couple boxes of loaded bullets, and reloading supplies. If you're only shooting, say, 3-5 rounds a year, it might be practical to just reload.

Just to point out an option (and not necessarily dissuading you against an AR, but rather offering a potentially less expensive option): Are you dead-set on an AR? At least around here, you can get a Savage Axis with a decent scope for $300 plus tax. I think $350 or so would get you a good setup, and $450-500 for the setup plus reloading. With the recoil of the .350 Legend being pretty mild, the recoil advantage of an AR might not be pronounced enough for the (potential) additional cost.

The Axis rifles won't win any long-range precision shooting competitions and you can't customize 'em like--say--a Remington 700-type rifle, but I know a few people with 'em and they're all good solid hunting guns.

[williaty]

Do you reload? Might do the math on a couple boxes of loaded bullets, and reloading supplies. If you're only shooting, say, 3-5 rounds a year, it might be practical to just reload.

Just to point out an option (and not necessarily dissuading you against an AR, but rather offering a potentially less expensive option): Are you dead-set on an AR? At least around here, you can get a Savage Axis with a decent scope for $300 plus tax. I think $350 or so would get you a good setup, and $450-500 for the setup plus reloading. With the recoil of the .350 Legend being pretty mild, the recoil advantage of an AR might not be pronounced enough for the (potential) additional cost.

We don't currently reload. With 9mm and 5.56, it's just never seen economically worth it. I did consider just getting a dedicated rifle for this. However, there's uppers starting at about $275. Also, since you're right about just shooting a handful of rounds a year, I thought using the lowers we already practice with would be the best use of the (very) limited amount of shooting in .350L. So no, I'm not married to the idea of just getting a different upper but so far it seems to make a lot of sense.

[MacWa77ace]

Anyone know the longest free float handguard that will fit on a 16" barrel with mid-length gas? My tape measure says about 9.5". Anyone here ever tried a build like that?

You have an A-frame front site on this? they make rails that will go around the site and even have a rail section in front, that would be the longest i'd think. maybe 15-15.5" ?

This one is not free float but I've seen them. They don't make sense to me because you have to take the front site off to install them so if you have to do that anyhow, just switch to a low profile gas block.

Branch option question: if you take an A-frame front sight/gas block and chop the sight part off, will it fit under a normal free float guard?

Just change to a low profile gas block for $30 bucks.

[Langenator]

Anyone know the longest free float handguard that will fit on a 16" barrel with mid-length gas? My tape measure says about 9.5". Anyone here ever tried a build like that?

You have an A-frame front site on this? they make rails that will go around the site and even have a rail section in front, that would be the longest i'd think. maybe 15-15.5" ?

This one is not free float but I've seen them. They don't make sense to me because you have to take the front site off to install them so if you have to do that anyhow, just switch to a low profile gas block.

Branch option question: if you take an A-frame front sight/gas block and chop the sight part off, will it fit under a normal free float guard?

Just change to a low profile gas block for $30 bucks.

This is for my "Most Triggering EBR" project - i.e., how many AWB features can I manage to include on a single rifle? Thus, the important piece is not the fixed front sight itself - it's the bayonet lug, which you can only get as part of the A-frame, M-16/M-4 type gas block.

Thus chop the sight part off, and either get a free float that comes right up behind the bayo lug, or maybe remove some metal from the handguard to allow a bayonet to be attached.

I know, it's a goofy idea, but I've already go practical ARs that do everything I want, so why not?

[boskone]

This is for my "Most Triggering EBR" project - i.e., how many AWB features can I manage to include on a single rifle? Thus, the important piece is not the fixed front sight itself - it's the bayonet lug, which you can only get as part of the A-frame, M-16/M-4 type gas block.

FWIW, though I dunno that it really changes your plans, a couple of YHM's flip-down front sights have bayonet lugs.

Mine does, I think, but I'd have to take my handguard off to find out. (I have a Magpul MOE, and I nipped the front sight cutout a bit so the flip-down sight would work.)

[Langenator]

This is for my "Most Triggering EBR" project - i.e., how many AWB features can I manage to include on a single rifle? Thus, the important piece is not the fixed front sight itself - it's the bayonet lug, which you can only get as part of the A-frame, M-16/M-4 type gas block.

FWIW, though I dunno that it really changes your plans, a couple of YHM's flip-down front sights have bayonet lugs.

Mine does, I think, but I'd have to take my handguard off to find out. (I have a Magpul MOE, and I nipped the front sight cutout a bit so the flip-down sight would work.)

YHM-9394-H is the part number (for the HK style ears). I don't know if it allows a longer handguard or not, and I haven't found flip-up sights on any list of scary features, but it's worth thinking about, for sure.

[williaty]

Found out I can't get my head down enough to see through the red dot with my full face respirator on. I'd like to patch this issue with a rail or mlok mounted laser. Is anyone aware of a really small laser-only package other than the LaserMax Uni-Max?

[woodsghost]

Found out I can't get my head down enough to see through the red dot with my full face respirator on. I'd like to patch this issue with a rail or mlok mounted laser. Is anyone aware of a really small laser-only package other than the LaserMax Uni-Max?

Aren't there lots of pistol lasers? Do you think one of those would work?

[williaty]

Found out I can't get my head down enough to see through the red dot with my full face respirator on. I'd like to patch this issue with a rail or mlok mounted laser. Is anyone aware of a really small laser-only package other than the LaserMax Uni-Max?

Aren't there lots of pistol lasers? Do you think one of those would work?

A rail mounted laser for a pistol would work but most of them are fairly tall. The only place I have a pic rail on this Banshee is down the top so I want something fairly flat so it doesn't get into my view through the red dot when I'm not using the full face respirator.

[MacWa77ace]

Found out I can't get my head down enough to see through the red dot with my full face respirator on. I'd like to patch this issue with a rail or mlok mounted laser. Is anyone aware of a really small laser-only package other than the LaserMax Uni-Max?

Aren't there lots of pistol lasers? Do you think one of those would work?

A rail mounted laser for a pistol would work but most of them are fairly tall. The only place I have a pic rail on this Banshee is down the top so I want something fairly flat so it doesn't get into my view through the red dot when I'm not using the full face respirator.

you can get an angled picatinny mount and have the laser offset to one side. This also helps to get around a front sight if you have one. The tiny lasers use tiny batteries with short lifespans.

[williaty]

you can get an angled picatinny mount and have the laser offset to one side. This also helps to get around a front sight if you have one. The tiny lasers use tiny batteries with short lifespans.

Hadn't thought about the battery issue, that's a good point. I don't anticipate needing a lot of runtime but small batteries are usually the hardest to find.

[12_Gauge_Chimp]

So I put a Geissele Posi-snap ambi safety on my AR and there's a slight bit of play when it's in the "fire" position and a slight bit of side to side movement.

It functions just fine as I did a test on it a few times before I put my AR back together, but the wobble kind of concerns me.

Is this normal or did I screw up the install somehow ?

[91Eunozs]

So I put a Geissele Posi-snap ambi safety on my AR and there's a slight bit of play when it's in the "fire" position and a slight bit of side to side movement.

It functions just fine as I did a test on it a few times before I put my AR back together, but the wobble kind of concerns me.

Is this normal or did I screw up the install somehow ?

Would have to see if your receiver is out of spec, or the 1:1M chance Geissele screwed up their machining, but initial thought is the safety detent or spring is too short. That said, a little wiggle isn’t going to make a difference unless it’s also wearing the receiver, but it shouldn’t have perceptible side-to-side play.

[12_Gauge_Chimp]

So I put a Geissele Posi-snap ambi safety on my AR and there's a slight bit of play when it's in the "fire" position and a slight bit of side to side movement.

It functions just fine as I did a test on it a few times before I put my AR back together, but the wobble kind of concerns me.

Is this normal or did I screw up the install somehow ?

Would have to see if your receiver is out of spec, or the 1:1M chance Geissele screwed up their machining, but initial thought is the safety detent or spring is too short. That said, a little wiggle isn’t going to make a difference unless it’s also wearing the receiver, but it shouldn’t have perceptible side-to-side play.

I'll swap out the detent and spring and see if that changes anything. Could be the spring is bunched up a little.

Everything functions as intended, though. It's just there's a tiny bit of play and then the safety wiggles side to side just a small amount.

ETA: So, I swapped out the detent spring and it appears the Geissele one is just a slight bit shorter than the factory one. So I put the factory one back in and the problem still exists, but it's not as obvious as before.

I fired off an email to Geissele just a minute ago asking about it and hopefully they'll respond soon. If they tell me this is normal due to variances between AR lowers (I'm using their safety on a Del-Ton DTI-15), I'll just leave it be. If not, I may have to reinstall the factory safety and try again.

ETA 2: I just double checked the side to side play on the safety and it's not as much as I initially thought. It's just a tiny little bit and doesn't really affect function at all. Mostly a cosmetic or aesthetic thing.

The front to back play still remains, but it's not as noticeable as when I had the Geissele spring in.

I'm probably worried over something stupid, but I'm pretty new to ARs, so I figured I'd ask.