KAC RAS doesn't want to fit PSA 10.5" barrel-dremel time? Now with Harbor Freight caliper pic!

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[ARCHIVED THREAD] - KAC RAS doesn't want to fit PSA 10.5" barrel-dremel time? Now with Harbor Freight caliper pic!

Posted: 7/20/2018 8:25:04 PM EDT

I've got a Palmetto 10.5" upper with FSB, trying to install a new Knight's RAS onto it. No Go. The front top leaf spring clip will not fit under the cap, due to the profile of the barrel. PSA's barrel is still 'thick' 1/2" after the FSB, so the top rial will not fit down around the gas tube, and under the cap.

Is filing off the underside of the RAS front 'nub' my only option?

Posted: 7/20/2018 8:36:51 PM EDT

[#1]

Ditch the PSA barrel. Save the Knight's RAS for something that will fit it, don't hack the RAS....

Posted: 7/20/2018 8:48:55 PM EDT

[#2]

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Quoted:
Ditch the PSA barrel. Save the Knight's RAS for something that will fit it, don't hack the RAS....

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...better option- I removed the roll pin and took out the leaf spring assembly. Fits snug. No dremelling this time.

~~EDIT. I take it back...bottom doesn't fit either.~~

Looks like you're right.

edit again- bottom is on

Posted: 7/20/2018 8:53:14 PM EDT

[#3]

In for pics....

Posted: 7/20/2018 8:55:22 PM EDT

[#4]

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In for pics....

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" />
view from the bottom, with top rail attached.

Posted: 7/20/2018 9:19:51 PM EDT

[#5]

" />

Posted: 7/20/2018 9:35:47 PM EDT

[#6]

What does the barrel measure aft of the fsb? It looks huge!? Optical illusion? Looks way bigger than .750".

Posted: 7/21/2018 3:47:55 AM EDT

[#7]

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http://i.imgur.com/cuunL1o.jpg" target="_blank">http://i.imgur.com/cuunL1o.jpg

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The RAS front spring clip can be very tight. Worst-case you might need to file a tiny amount off to get it to fit, but you shouldn't need to remove it. Barrel profile won't matter; a RAS can fit a medium and heavy profile barrel without issue.

BTW... is that an airsoft CQD mount I see there?

Posted: 7/21/2018 8:16:25 AM EDT

[#8]

Quote History

Quoted:

The RAS front spring clip can be very tight. Worst-case you might need to file a tiny amount off to get it to fit, but you shouldn't need to remove it. Barrel profile won't matter; a RAS can fit a medium and heavy profile barrel without issue.

BTW... is that an airsoft CQD mount I see there?

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I'd have to file quite a bit off...it's nowhere near fitting down far enough.

...and probably, I paid $5 for it used!

Posted: 7/21/2018 8:31:38 AM EDT

[#9]

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Quoted:

BTW... is that an airsoft CQD mount I see there?

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@krdt
How can you tell? ^^^^

Posted: 7/21/2018 8:55:08 AM EDT

[#10]

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Quoted:

@krdt
How can you tell? ^^^^

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I think -now that I look at it closer- the ends are 'squared' off, and not rounded-?

Posted: 7/21/2018 9:26:50 AM EDT

[#11]

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I think -now that I look at it closer- the ends are 'squared' off, and not rounded-?

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Yes it's fake.

Posted: 7/21/2018 2:46:39 PM EDT

[#12]

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Quoted:
@krdt
How can you tell? ^^^^

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Quoted:

Quoted:

BTW... is that an airsoft CQD mount I see there?

@krdt
How can you tell? ^^^^

Mainly that the edges are really sharp and not gently rounded. Also the logo and overall dimensions don't look quite right, and there appears to be some rough machining/chatter marks on the hook attachment point as well.

Posted: 7/21/2018 3:25:34 PM EDT

[#13]

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Quoted:
I'd have to file quite a bit off...it's nowhere near fitting down far enough.

...and probably, I paid $5 for it used!

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Quoted:

Quoted:

The RAS front spring clip can be very tight. Worst-case you might need to file a tiny amount off to get it to fit, but you shouldn't need to remove it. Barrel profile won't matter; a RAS can fit a medium and heavy profile barrel without issue.

BTW... is that an airsoft CQD mount I see there?

I'd have to file quite a bit off...it's nowhere near fitting down far enough.

...and probably, I paid $5 for it used!

If you try to shove the tongue directly under the cap, it might take a lot of force or seem like it won't fit at all. The best way I've found is to push the spring clip notch over the gas tube a little ways back from the end cap. Then with the RAS at about a 35 degree angle, slip it forward on the gas tube and get an edge under the cap. Once you have that edge under the cap, you can use it as leverage to work the rest of it under. The fit on a new RAS will be very tight, but it also results in a solid rail without rattles or movement. While it'll obviously work without the spring clip, I'd leave it installed; it's there for a reason and results in a more solid lock up.

I highly doubt the barrel itself is causing any problems as you can use a RAS with a heavy/SOCOM profile barrel. Just have to ask - you sure the RAS is authentic?

Posted: 7/21/2018 4:12:39 PM EDT

[#14]

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> you can use a RAS with a heavy/SOCOM profile barrel. Just have to ask - you sure the RAS is authentic?

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This was my initial thought.

And thanks for the heads up on the CQD mount.

Posted: 7/22/2018 1:29:35 AM EDT

[#15]

You should have no problem getting the RAS on that upper with the spring clip installed. I had an RAS on my PSA 10.5" upper for years, un-installing and re-installing it multiple times without issue.

Sounds like you were doing something wrong.

Posted: 7/23/2018 1:21:14 PM EDT

[#16]

Quote History

Quoted:

If you try to shove the tongue directly under the cap, it might take a lot of force or seem like it won't fit at all. The best way I've found is to push the spring clip notch over the gas tube a little ways back from the end cap. Then with the RAS at about a 35 degree angle, slip it forward on the gas tube and get an edge under the cap. Once you have that edge under the cap, you can use it as leverage to work the rest of it under. The fit on a new RAS will be very tight, but it also results in a solid rail without rattles or movement. While it'll obviously work without the spring clip, I'd leave it installed; it's there for a reason and results in a more solid lock up.

I highly doubt the barrel itself is causing any problems as you can use a RAS with a heavy/SOCOM profile barrel. Just have to ask - you sure the RAS is authentic?

View Quote

yeah- no doubt on that, I got it from a local vendor.

Posted: 7/23/2018 1:36:25 PM EDT

[#17]

I put an M4 RAS onto a Colt 11.5 HRT barrel. It was snug going on (which I prefer), but it all fit without issue. The HRT barrel has a heavy profile.

Posted: 7/23/2018 2:32:36 PM EDT

[#18]

Ok, thanks for the help...I'll try again tonight. I'll measure that barrel profile, too...and shop for a real sling mount!

Posted: 7/24/2018 2:54:28 PM EDT

[#19]

There's an EE ad currently for a PSA 10.5" upper with RAS M4, same fitment issue.

Posted: 7/25/2018 4:12:43 PM EDT

[#20]

I had to use a BFH to get my M5 RAS installed on my M16A4 clone. That sucker is never coming back off

Posted: 7/27/2018 10:26:21 PM EDT

[#21]

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There's an EE ad currently for a PSA 10.5" upper with RAS M4, same fitment issue.

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...saw that. Same barrel.

Posted: 7/27/2018 10:46:21 PM EDT

[#22]

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Quoted:
...saw that. Same barrel.

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Quoted:

Quoted:
There's an EE ad currently for a PSA 10.5" upper with RAS M4, same fitment issue.

...saw that. Same barrel.

My thoughts exactly.

Posted: 7/28/2018 7:27:36 PM EDT

[#23]

....and here we go. The Harbor Freight digital calipers don't lie (they may fudge a little...) I think that's a wee bit larger than a 'heavy barrel' is, right? However, even without the leaf up front, it locks up tight. I may modify the leaf bushing, or even take the barrel down at some point, not sure.