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Posted: 9/12/2003 12:18:53 PM EDT
10" or 10.5" from a shortened M4 1:7 barrel?
Link Posted: 9/12/2003 1:15:14 PM EDT
10.3 inch is the length for the Crane CQB upper
Link Posted: 9/12/2003 1:34:41 PM EDT
[Last Edit: 9/12/2003 1:35:32 PM EDT by Horik]
If your looking to buy and 10" or 10.5" is your choice.......Go with 10.5"
Link Posted: 9/12/2003 2:22:20 PM EDT
here is a picture [img]http://www.thermaldynamics.com/pictures/guns/cqbspr.jpg[/img]
Link Posted: 9/12/2003 3:01:57 PM EDT
SMGLee, Is that a KAC RIS or RAS?
Link Posted: 9/13/2003 12:39:02 AM EDT
Mr Pink I saw that you had a upper on order from MSTN.You should use a RAS with it.They have the same contour as the M4.SJR556.
Link Posted: 9/13/2003 1:28:16 AM EDT
[Last Edit: 9/13/2003 1:31:15 AM EDT by SMGLee]
It is a RIS. the barrel under neath is the skinny profile. The barrel comes standard with the KAC M4QD flash hider. Upgraded COTS 5 coil extractor spring and rubber bumper and McFarland gas ring.
Link Posted: 9/13/2003 2:23:40 AM EDT
[Last Edit: 9/13/2003 2:24:11 AM EDT by amuroray]
Upgraded COTS 5 coil extractor spring and rubber bumper and McFarland gas ring.
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SMGLee, that's a sweet looking upper. What is "rubber bumper"?
Link Posted: 9/13/2003 2:34:22 AM EDT
[Last Edit: 9/13/2003 2:36:11 AM EDT by dewatters]
Originally Posted By amuroray: What is "rubber bumper"?
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He is referencing an improved extractor spring insert. It is a nub of rubber that is placed inside the coils of the extractor spring.
Link Posted: 9/13/2003 4:01:32 AM EDT
SMGLee is correct, its a RIS. Crane apparently sticking with what the 10,000 guys they already support already have vs. going to the M4 RAS. For example, since the RIS they already have on their M4A1 Carbine 14.5" upper is numbered 1-13 from front to rear, when the RIS equipped CQB uppers are issued, they will be "addressed" the same, share the same repair parts, manual, etc. This is what life-cycle-cost is all about.
Link Posted: 9/13/2003 4:31:42 PM EDT
Coldblue, What was the logic behind the front to rear numbering? Seems like this would be confusing with carbine and rifle length systems in use.
Link Posted: 9/14/2003 5:52:22 AM EDT
Fact is, the USSOCOM front-to-rear/1-13 address numbering predates the ARMY numbering the upper receivers rear-to-front/1-13 by a couple of years; and of course the subsequent RAS numbering 14-forward. We were perplexed about this as well because the for the Army tests, we initially submitted the USSOCOM RIS. SO they had to know the USSOCOM numbering system. In gact, I doubt they even considered numbering the upper receiver until they saw the numbers on the RIS. Why they reversed it is anybody's guess. I have heard everything from inter-service rivalry (because the "Navy" had done the RIS/USSOCOM thing), to once they were inspired to address rail grooves, that the upper receiver being the "dominant" element, in front of which many generations of rail forends would modify, that #1 would start there. Also consider from the USSOCOM side that their uppers are usually covered by an ACOG, M68, Back-Up Iron Sight, etc. However, this difference has caused some minor confusion problems like with some Ranger units initailly RIS'd by USSOCOM/Navy (Crane); but now get supply support like RAS lower replacements that are numbered differently than their RIS uppers, because the RAS parts are what is illustrated in their M16/M4 TM...2/3&P's.
Link Posted: 9/14/2003 11:01:45 AM EDT
Coldblue, Interservice rivalry is certainly believable in light of some other stories I've heard. Are the numbers even worth having, in your opinion? Quick
Link Posted: 9/14/2003 11:21:47 AM EDT
Originally Posted By SMGLee: 10.3 inch is the length for the Crane CQB upper
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Would like to talk you into a listing of the details on the various features of the Crane CQB upper, in particular on improvements to the gas system/bolt. Also was wondering if the bayonet still works with this length barrel. Thanks John
Link Posted: 9/14/2003 12:08:16 PM EDT
[Last Edit: 9/14/2003 12:08:59 PM EDT by SMGLee]
John, I IM you with the difference, there isn't really that much difference. the extractor spring, McFarland rign, PRI gas buster, 10.3 inch barrel with .070 gas port opening and a KAC QD flash hider. The bayonet will not work, the front sight post is stock inventory item so therefor you see the lug underneath.
Link Posted: 9/14/2003 12:11:49 PM EDT
Chen- I was wondering if the PRI gas tube is seeing any use in this model?
Link Posted: 9/14/2003 12:57:39 PM EDT
[Last Edit: 9/14/2003 12:57:50 PM EDT by SMGLee]
I don't think so, but I can't be sure. Out of four guns they tested, I remember several gas tubes failed plus an extractor and an extractor spring.
Link Posted: 9/14/2003 4:37:46 PM EDT
Are these the same uppers that MSTN sells?
Link Posted: 9/14/2003 4:52:48 PM EDT
Link Posted: 9/14/2003 7:03:26 PM EDT
Originally Posted By Redbone: Are these the same uppers that MSTN sells?
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Yes, same config. by LMT for Crane AFAIK! Apparently the newer ones have a slightly heavier bbl. profile. The others are standard M4 I believe.
Link Posted: 9/15/2003 3:21:19 PM EDT
If we're talking about MSTN LMT shorty uppers then they do not use or even like the PRI gas tubes. They run 100% reliably, even full auto with the regular tube. Wes could give you more detailed info on their success and testing. IMHO, even with some good Colt and BM short uppers out there, the LMT 10.5 is the ONLY way to go these days. It requires no tweaking to run PERFECTLY and is SCARY ACCURATE.
Link Posted: 9/15/2003 5:33:13 PM EDT
I could'nt agree more! Scary accurate is a good description. The upper runs as well as anything I own, if not better!
Link Posted: 9/16/2003 6:28:28 AM EDT
Originally Posted By FlyNavy: If we're talking about MSTN LMT shorty uppers then they do not use or even like the PRI gas tubes. They run 100% reliably, even full auto with the regular tube. Wes could give you more detailed info on their success and testing. IMHO, even with some good Colt and BM short uppers out there, the LMT 10.5 is the ONLY way to go these days. It requires no tweaking to run PERFECTLY and is SCARY ACCURATE.
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Then why do they sell them....the "PRI fat boy" gas tubes I mean?
Link Posted: 9/16/2003 10:55:51 AM EDT
For many reasons. They do make M4's run better apparently and can do wonders to franken shorty's where a short bbl. can reek havoc with cycling problems! The LMT does not need one.
Link Posted: 9/16/2003 11:26:03 AM EDT
Thank you for your various replies. I'm going to have to look more into Wes's LMT upper...Wes you can chime in on the details they spoke of at any point bud!
Link Posted: 9/16/2003 2:16:41 PM EDT
No need to look.........just open your wallet[:D] Believe me you won't be sorry! I love mine and may get another in the future. I got one from the original run with the slimmer bbl. profile standard M4.........The ones he has now are a bit heftier and therefore should be slightly better. Either way they are durable as hell and the accuaracy is amazing for sure!
Link Posted: 9/16/2003 11:49:02 PM EDT
Good deal. I've used a couple if 11.5" guns and the close quarters handling characteristics are much improved over the base 14.5" carbine.
Link Posted: 9/17/2003 3:31:09 PM EDT
Link Posted: 9/17/2003 3:38:45 PM EDT
Link Posted: 9/18/2003 1:13:40 PM EDT
Originally Posted By QUICK: Coldblue, Interservice rivalry is certainly believable in light of some other stories I've heard. Are the numbers even worth having, in your opinion? Quick
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The numbers are worth having. For example, when an operator needs to mount his M203, but his PAQ-4 is presently mounted and zeroed on the top rail, the laser needs to be moved and re-zeroed to the right rail. If he has done this before, remembers the address he uses on the right rail, and the now reversed elevation & wingage changes that may or may not be required, then he's good to go.
Link Posted: 9/18/2003 4:46:49 PM EDT
I'm sure the guy could also lign the front of the PAQ-4 with the front of the RAS or 2nd slot- or wherever he mounts it... It's what all of us did before numbere pannels. It worked then it should still work. Or of course he couldjust keep the Paq-4 on the side and the 203 sight on top. and then he wouldn't have to worry about: 1 The location of mounting 2 untieing his dummy cord from the weapon and tieing it to his ruck frame or whatever. (The weight isn't enough for me to want to screw with it personally. (most units require paq-4's and flashlights, optics, etc to be dummy corded. Yep I know odds are 99.9% of the time that item will stay on but because of unit commanders, responsibility, and lost items nearly all of us have to tie off shit anyway.
Link Posted: 9/18/2003 7:13:36 PM EDT
Here is a thread about 10" AR's. [url]http://www.ar15.com/forums/topic.html?b=3&f=118&t=170476&page=1[/url]
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