KAC/BCM gun with 13.8" Troy Alpha rail

AR/M4 AR General Discussion
1

I started a thread a little while ago about my loose URX II rail. After finding out I needed special, expensive tools in order to service it, my desire to own an SR-15 cooled a little. I know the KAC guns are fantastic, and I will probably own one someday, but the servicing issue combined with the price of the upper alone put me off a bit and I ended up ordering a 16" BCM midlength BFH upper and the new FF 13.8" Troy Alpha rail. The cost came out to a few hundred less than the KAC upper, so I can put that money towards an optic and ammo.

I thought I’d do a post on it since the rail is fairly new to the market and I just finished installing it tonight.

The Alpha is a lightweight “tube-style” rail that accommodates bolt-on rail segments that can be placed at 8 positions depending on what you want to mount on it. I’ll probably just hang a light on there, and maybe an RVG, since that’s what I have on my other guns.

What drew me to the Alpha was the integral front sight, like the URX II, but the removable rail segments, lower price and ability to use just the standard barrel nut for mounting gave the Troy rail the edge in my opinion.

I forgot to take pics of the mounting process, but it’s very simple and solid. You remove the muzzle device, FSB and barrel, discard the delta ring, spring and snap ring, and then reassemble with only the barrel nut installed. I chose to grind down the FSB so I could have a pinned unit. My wimpy rechargeable Dremel wasn’t powerful enough, so I used a hacksaw and then went out and got a $50 bench grinder to finish the job.

The hour I spent with the grinder was one of the most relaxing in recent memory. A very satisfying experience.

After a few test fits with the rail, I got the FSB down to where it didn’t contact the sight when folded down.

The rail fits over the barrel nut and then rotates to “lock” into place much like the bolt does when it locks against the barrel extension. Then you simply tighten down the three bolts that press the clamps against the nut. There’s also a small anti rotation tab on the left side next to the receiver that ensures it doesn’t go anywhere. I’m pretty impressed at how simple the system is. It feels rock solid. There’s very little gap between the rail and receiver.

I will update after my first range trip tomorrow.

2

Cool. Thanks for the pics.

3

Very cool. Now that I’ve finally finished my shiny new 20" build, a setup like this is in my future.

4

Great post and great looking gun!
Have fun and tear it up!

5

Nice write up and rifle.

6

Took it out today and ran 4 mags (USGI and Pmags) through it. Not a significant number, but I was interested more in checking function. No problems at all. I was a little concerned about accuracy since I’ve only installed a barrel a few times, and I was sure I’d have found a way to screw it up, but the sights were pretty much dialed in right out of the box. The hits were dead center at 25yds, and about 3" low. I think I’ll go for a 200yd zero when I take it out again. That should cover me for most ranges I’ll be shooting.

7

I’ve never had a Troy rail match the upper rail that well.

I wonder if the new mounting system is making that happen…

Looks good.

8

Were there a lot of complaints about it? Maybe they listened?

9

Looks very very nice. I’ve been looking for a pic of the sight to see if my preferred night sight will drop in and it looks like it will, I think I’m sold now.

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I have a KAC SR15 barrel,gas block,gas tube and bolt carrier group I bought off this site. I was thinking about using the Troy Alpha but I don’t think it will clear the KAC gas block:(:frowning:

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Who ever installed the URX rail should have tightened it for you. If it came loose it was installed improperly.If it was a factory instal then it would have been fixed at no charge as well.We are working on a more inexpensive wrench solution.

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III, thanks for the update and as asked above your post will the Troy Alpha clear the KAC gas block? TIA

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Not sure , you can certainly go at it with a dremel and get it to work.

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Hi, Maybe you could help me decide if the Alpha is the right rail for my new build.

Anyway, it’s funny that you posted this, as I’m doing another build right now that includes a BCM 16" middy stainless barrel. I’ve pretty much decided on or purchased everything except the rail.

BUT I’ve been having a H3LL of a time deciding. I have a VTAC Extreme (same as Troy) on another rifle and while I love the feel and utility of the rail the way the rail mounts on the barrel nut is less than stout IMO. And Troy has admitted that they actually had problems with it.

So now they have the Alpha and I’m most curious about the new mount. Because I want something that isn’t going to come apart, even under severe conditions.

So how solid is it?

The other option I like is the new Daniel Defense MFR which is similar, but very expensive and less developed.

This may be my first post on M4Carbine. I’ve always thought this was a superior forum, but had trouble getting the finalization of my account done until a couple of weeks ago. I come to this forum to learn about the SCAR rifles, as I own a couple. The info on the SCARs here, is better than it is on the manufacturers forum.

I really appreciate this post and your response. Thank you.