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Posted: 4/8/2007 7:54:09 PM EDT
I ordered one for a carbine, but on the package it says: AR15, CAR 15, AR10/SR25

The question I have is, is that is the one spring really for all systems? Because it is longer than a rifle length spring and seems excessively "stiff" for a carbine. I have not shot with it yet though.

Is this normal, or did I receive a rifle length spring?
Link Posted: 4/8/2007 8:33:00 PM EDT
[Last Edit: 4/8/2007 8:46:01 PM EDT by blakey6551]
The new flat springs are for both lengths. If it causes a malfunction, cut it down slightly.
Link Posted: 4/13/2007 4:57:41 PM EDT
Serioulsy, that seems pretty lame. How could one spring work for both considering that the spring is going to fit into a carbine receiver ext and it is longer than an A2 spring?


Doesn't cutting a spring change its structural properties?
Link Posted: 4/13/2007 7:24:52 PM EDT
[Last Edit: 4/13/2007 7:25:23 PM EDT by 308Sako]
Actually the flat spring is better because the force it exerts is evener in it's application. The length compressed is shorter than a regular carbine spring if my memory serves me. I run this spring in my Cr6724, and with a 6 position on the 7.62 x 39 - 16". No problems what so ever.
Link Posted: 4/19/2007 12:15:13 PM EDT
But a 7.62 imparts more rearward energy than the 556. Have you tried the buffer spring in a 556 upper? With what buffer?
Link Posted: 4/19/2007 6:30:32 PM EDT
[Last Edit: 4/19/2007 6:38:58 PM EDT by DBR]
Personally, I would not use the Tubb's spring. I have three of them that I bought before I realized what they are. The ones I have I got for A2 buffer systems. The stock Colt Spring has 43 turns. The Tubb's spring has 32 turns. This has several consequences: the spring is much stiffer in battery - I would guess 50%. The spring rate is completely different than the original design, it returns the bolt to battery VERY hard - think SLAM FIRE.

I like flat wire springs for their mechanical properties. I do not agree with second guessing the specs of such an integral part of such a proven system. Maybe they will get it right the second time. For now I use stock Colt springs.
Link Posted: 4/20/2007 7:50:43 AM EDT
Hmm.
Link Posted: 4/20/2007 8:11:47 AM EDT
I love my flat-wound Tubb's ISMI recoil spring in my 16" Middie. Care to sell a like new one cheap?
Link Posted: 4/20/2007 8:12:47 AM EDT
Can't comment on your spring but I have run an ISMI spring before.

I purchased an ISMI spring from G&R Tactical over a year ago.


I counted 32 turns if you don't count the ends. It's a stainless alloy and chrome silicon type spring. Cost me $20 and whoa nelly does it makes things stiff. Pulling back on the chargind handle requires a noticeable amount of additional strength. I figured this would be a good thing as it would slow down the carrier. Well it certainly did that! Running this spring in conjunction with an MGI RRB and an H&K mag caused short stroking after EVERY ROUND. Switching to USGI mags caused it very infrequently but enough to make me re-think all this heavy buffer and spring business.

I got rid of the H&K mag because that's plain bullshit that a $10 USGI mag out paced this $50 dollar wonder shit mag. I of course STOPPED running the ISMI spring in favor of the factory carbine spring. I held onto the spring because I think it'll be better suited in taming the carrier on a 9mm build.

It should be noted that, running the ISMI spring, and a regular 3.x OZ carbine buffer ALSO short stroked with that H&K mag. Needless to say both the mag and that spring aren't running anymore in my Bushy.

-Moco
Link Posted: 4/20/2007 12:23:56 PM EDT

Originally Posted By TheMocoMan:
Can't comment on your spring but I have run an ISMI spring before.

I purchased an ISMI spring from G&R Tactical over a year ago.
www.gandrtactical.com/images/archive/ISMI/Car%20buffer%20spring.JPG

I counted 32 turns if you don't count the ends. It's a stainless alloy and chrome silicon type spring. Cost me $20 and whoa nelly does it makes things stiff. Pulling back on the chargind handle requires a noticeable amount of additional strength. I figured this would be a good thing as it would slow down the carrier. Well it certainly did that! Running this spring in conjunction with an MGI RRB and an H&K mag caused short stroking after EVERY ROUND. Switching to USGI mags caused it very infrequently but enough to make me re-think all this heavy buffer and spring business.

I got rid of the H&K mag because that's plain bullshit that a $10 USGI mag out paced this $50 dollar wonder shit mag. I of course STOPPED running the ISMI spring in favor of the factory carbine spring. I held onto the spring because I think it'll be better suited in taming the carrier on a 9mm build.

It should be noted that, running the ISMI spring, and a regular 3.x OZ carbine buffer ALSO short stroked with that H&K mag. Needless to say both the mag and that spring aren't running anymore in my Bushy.

-Moco


That is what I was afraid of, short-stroking (SS). I have had even Wolfe XP spring induce SS. I did not buy this on purpose, it came with a CTR stock assembly my buddy bought and I am doing the build for him.

I am not sure i like the idea of snipping the wire either, doesn't that change the springs structural properties?
Link Posted: 4/20/2007 12:25:29 PM EDT

Originally Posted By JackalAR:
I love my flat-wound Tubb's ISMI recoil spring in my 16" Middie. Care to sell a like new one cheap?


Assuming it is a carbine buffer, what buffer weight do you run? What make barrel?
Link Posted: 4/20/2007 12:38:57 PM EDT
[Last Edit: 4/20/2007 12:40:25 PM EDT by JackalAR]

Originally Posted By chewbacca:

Originally Posted By JackalAR:
I love my flat-wound Tubb's ISMI recoil spring in my 16" Middie. Care to sell a like new one cheap?


Assuming it is a carbine buffer, what buffer weight do you run? What make barrel?


Sabre Defence, CMT "H" buffer, CMT enhanced carrier. Cycles everything fine...bolt locks back everytime. The first 100 rounds through her were 45gr. WWB JHP's. I'd say if this spring causes short stroking, you have other issues.
Link Posted: 4/20/2007 12:44:51 PM EDT
FWIW I had the round tubbs springs on a couple 20" ARs and it caused them to short-stroke with Wolf and Barnaul. Switched back to regular springs and the problem went away. I have the flat spring in a couple rifles and have had no issues whatsoever with them.
Link Posted: 4/20/2007 1:32:41 PM EDT
To clarify though, the new flat-spring is the same length (read same spring) for both rifle and carbine length?
Link Posted: 4/20/2007 1:39:22 PM EDT

Originally Posted By chewbacca:
To clarify though, the new flat-spring is the same length (read same spring) for both rifle and carbine length?


Yes, that is the way I understand Tubbs (SSS) literature which accompanied the spring.

Note I have run this with the A2 stock, and a 6 position aftermarket on both the 24" Colt 5.56, and the 16" Colt 7.62 x 39. I have also played with the CWS during this interval and have found no issues which I felt were spring related. I did feel when installing the spring that there was a smooth, or more balanced feel to it's motion during manual compression.
Link Posted: 4/20/2007 1:43:17 PM EDT
CWS?
Link Posted: 4/20/2007 1:45:14 PM EDT
Also a Tubb product

Carrier Weight System
Link Posted: 4/20/2007 7:36:17 PM EDT
[Last Edit: 4/20/2007 7:45:03 PM EDT by DBR]
JackalAR PM me.

Even though the relaxed spring is the same length as a stock rifle spring reducing the number of coils increases the spring rate ie the spring gets stiffer faster for each inch of compression. That is at least one of the reasons why the in battery force is so much higher.

All the spring has to do is strip a round from the mag and lock the bolt into battery with some reserve force to overcome crud and inadequate lube. This is a balancing act. If the spring is too stiff then the bolt will short stroke under the same conditions. The unlocking is mostly controlled by the gas system and the hammer spring.

ISMI did make a round wire spring for awhile but Marc at ISMI told me a couple of weeks ago that they don't plan to make any more. I had called him about the issues I had with the flat spring design. He said that's what Tubb wanted. Doesn't make sense to me.
Link Posted: 4/20/2007 8:53:16 PM EDT
[Last Edit: 4/20/2007 8:54:07 PM EDT by scottryan]
Why? Why? Why?

If your gun doesn't run well with the stock parts, then this stuff is just a band aide solution.
Link Posted: 4/20/2007 9:20:01 PM EDT
I put one on my 10.5". I order t get the bolt to lock back after the last round I had to trim some length off. Other than that it's been fine.
Link Posted: 4/20/2007 9:27:20 PM EDT

Originally Posted By scottryan:
Why? Why? Why?

If your gun doesn't run well with the stock parts, then this stuff is just a band aide solution.


In my case the rifle(s) run fine and am looking to investigate the limits of performance without harming the rifle(s.) My application for the CWS is for long distance slow fire loads which are using heavy bullets and tend to have considerable residual pressure. That said I also discovered that; the CWS is also been beneficial in running heavier than normal bullets from the carbine length 7.62 x 39 helping to compensate for dwell time issues there. Please also note that all this tweaking has been with Home Brewed Ammunition. If I were to run a rifle for factory or issue ammunition I would not be changing or adding parts with the one exception of the chrome silicon springs which have such a superior life expectancy.
Link Posted: 4/20/2007 10:26:19 PM EDT
[Last Edit: 4/20/2007 10:31:35 PM EDT by DBR]
308Sako:

I agree with you re the superior properties of CS and flat wire springs and for your purposes maybe specs need to be altered. The stock Colt buffer spring is one of the most under stressed springs I have seen i a firearm. If it is decently made it should last forever. Carbines are another matter.

It frustrates me that a reputable company (ISMI) known for quality products does not offer a stock spec flat wire spring and instead only offers one that cannot be matched with original specs. I wanted the flat wire spring for its superior properties not to change the dynamics of my rifles.

Also, it does not go "BOING".

It's my understanding that Tubb's purpose in designing this spring was to reduce the bump in the recoil cycle to allow faster recovery of sight picture during hipower match shooting. From what I have read high power, heavy bullet loads tend to be on the warm side. He thinks it works for this purpose. I don't think he intended it to be for general use.
Link Posted: 4/20/2007 11:47:05 PM EDT
[Last Edit: 4/21/2007 7:22:33 AM EDT by chewbacca]

Originally Posted By scottryan:
Why? Why? Why?

If your gun doesn't run well with the stock parts, then this stuff is just a band aide solution.


No shit; that are my thoughts on it as well. Like I said, this spring came with a buddy's CTR purchase (that I gave the 'ok' on) and I am curious...for those who like, I will trade it for a standard spring.

Link Posted: 4/21/2007 3:39:59 AM EDT
I had the ISMI spring & H2 buffer in my 16" middy. It worked well with regular ammo, but would short stroke on Wolf and Barnaul ammo. I purchased a bunch of Chrome Silicone standard springs from Brownells and they work fine.

I use the CS flat spring on my 18" middy with rifle length stock. It eats all ammo.
Link Posted: 4/21/2007 5:26:44 AM EDT

Originally Posted By TheMocoMan:
Can't comment on your spring but I have run an ISMI spring before.

I purchased an ISMI spring from G&R Tactical over a year ago.
www.gandrtactical.com/images/archive/ISMI/Car%20buffer%20spring.JPG

I counted 32 turns if you don't count the ends. It's a stainless alloy and chrome silicon type spring. Cost me $20 and whoa nelly does it makes things stiff. Pulling back on the chargind handle requires a noticeable amount of additional strength. I figured this would be a good thing as it would slow down the carrier. Well it certainly did that! Running this spring in conjunction with an MGI RRB and an H&K mag caused short stroking after EVERY ROUND. Switching to USGI mags caused it very infrequently but enough to make me re-think all this heavy buffer and spring business.

I got rid of the H&K mag because that's plain bullshit that a $10 USGI mag out paced this $50 dollar wonder shit mag. I of course STOPPED running the ISMI spring in favor of the factory carbine spring. I held onto the spring because I think it'll be better suited in taming the carrier on a 9mm build.

It should be noted that, running the ISMI spring, and a regular 3.x OZ carbine buffer ALSO short stroked with that H&K mag. Needless to say both the mag and that spring aren't running anymore in my Bushy.

-Moco


Damn, that's one stiff spring! Thank you for sharing your experience here.

If you don't mind my asking, what configuration was the rifle (i.e., 20" rifle, 16" mid-length, 16" carbine, 14.5" carbine, etc...)?
Link Posted: 4/21/2007 6:09:57 AM EDT

Originally Posted By CitySlicker:
Damn, that's one stiff spring! Thank you for sharing your experience here.

If you don't mind my asking, what configuration was the rifle (i.e., 20" rifle, 16" mid-length, 16" carbine, 14.5" carbine, etc...)?


It's the 2005 AR15.com SEBR (Bushmaster 14.5 with 1:7) the regular old carbine spring that came with it works best. Mags are USGI D&H teflon coated, MagPul followers, the best. Ammo was/is Black Hills FMJ 55gr Blue Box (~3,000fps). I still run the MGI Rate-Reducing Buffer becuase it indeed does what it claims to do. The compression of the ISMI spring is just too much. Although with the USGI mags this insane combo worked 98% of the time, it would short stroke randomly and I don't want that ever. With the regular carbine spring, even the 7.1oz of buffer weight doesn't cause this problem.

I still have the ISMI spring becuase I think in my next 9mm build the "short stroking" capabilites might be a good thing to help prevent bolt catch breakages. After all a $20 springs sure beats the $90 9mm Q-Buffer!
Link Posted: 4/21/2007 9:14:32 AM EDT

Originally Posted By TheMocoMan:
It's the 2005 AR15.com SEBR (Bushmaster 14.5 with 1:7) the regular old carbine spring that came with it works best. Mags are USGI D&H teflon coated, MagPul followers, the best. Ammo was/is Black Hills FMJ 55gr Blue Box (~3,000fps). I still run the MGI Rate-Reducing Buffer becuase it indeed does what it claims to do. The compression of the ISMI spring is just too much. Although with the USGI mags this insane combo worked 98% of the time, it would short stroke randomly and I don't want that ever. With the regular carbine spring, even the 7.1oz of buffer weight doesn't cause this problem.

I still have the ISMI spring becuase I think in my next 9mm build the "short stroking" capabilites might be a good thing to help prevent bolt catch breakages. After all a $20 springs sure beats the $90 9mm Q-Buffer!


Wow, it would have been even worse in a 14.5" mid-length.

Well anyway, thanks for answering.

Justin
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