DocMedic Posted February 10, 2012 Share Posted February 10, 2012 Long story short: Built a new rifle, using a Carbine length Buffer tube, Bought a JP Buffer spring for a Carbine. Received it in the mail, it looked a bit too long, but packaging states CARBINE. Put it in the rifle, and the rifle barely cycles with Gas block completely OPEN. Only way I was able to get it to run 100% was by throwing a suppressor on it. Had couple people cycle the action and they also feel that its over sprung. So Can someone with a Carbine length JP buffer spring do me a favor and measure it and post it here or PM me please. Thank you. Link to comment Share on other sites More sharing options...
MarkCO Posted February 10, 2012 Share Posted February 10, 2012 Long story short: Built a new rifle, using a Carbine length Buffer tube, Bought a JP Buffer spring for a Carbine. Received it in the mail, it looked a bit too long, but packaging states CARBINE. Put it in the rifle, and the rifle barely cycles with Gas block completely OPEN. Only way I was able to get it to run 100% was by throwing a suppressor on it. Had couple people cycle the action and they also feel that its over sprung. So Can someone with a Carbine length JP buffer spring do me a favor and measure it and post it here or PM me please. Thank you. Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. Link to comment Share on other sites More sharing options...
DocMedic Posted February 10, 2012 Author Share Posted February 10, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. Ugh, Is it possible to just cut it a couple coils? or should I just order a different spring? Link to comment Share on other sites More sharing options...
MarkCO Posted February 10, 2012 Share Posted February 10, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. Ugh, Is it possible to just cut it a couple coils? or should I just order a different spring? I just think they are too stiff for the carbine length tubes. Link to comment Share on other sites More sharing options...
Colodrew Posted February 10, 2012 Share Posted February 10, 2012 Curtis, I just changed from a rifle length to carbine length JP buffer and spring and had zero problems on my CTR-02. My buffer spring measures 11.25". Link to comment Share on other sites More sharing options...
Mark Gale Posted February 10, 2012 Share Posted February 10, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. Link to comment Share on other sites More sharing options...
Brian Payne Posted February 10, 2012 Share Posted February 10, 2012 I am using a JP Carbine buffer spring in an UBR stock with no problems. I am away from home so I can't measure, but I am sure if you give JP a call they will help with the situation. Link to comment Share on other sites More sharing options...
Outsydlooknin75 Posted February 10, 2012 Share Posted February 10, 2012 Any possibility that you got a 308 carbine buffer spring? Sent from my PG06100 using Tapatalk Link to comment Share on other sites More sharing options...
ericm Posted February 10, 2012 Share Posted February 10, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. I hate to use the word "experience", but....you are mistaken. I can demonstrate, by EXPERIENCE, that firing pin momentum can be and has been responsible for "slam fire" events in AR pattern guns. It is decoupled from bolt momentum, which, by the way, is not "stopped by the chambered cartridge before it can lock"....(???) Experience.....gather it, learn from it, love it. ....and some technical expertise might not hurt either... ericm Link to comment Share on other sites More sharing options...
Bryan 45 Posted February 10, 2012 Share Posted February 10, 2012 (edited) I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. Are you confusing out of battery ignition w/ slam fire? Edited February 10, 2012 by Bryan 45 Link to comment Share on other sites More sharing options...
gng4life Posted February 10, 2012 Share Posted February 10, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. I hate to use the word "experience", but....you are mistaken. I can demonstrate, by EXPERIENCE, that firing pin momentum can be and has been responsible for "slam fire" events in AR pattern guns. It is decoupled from bolt momentum, which, by the way, is not "stopped by the chambered cartridge before it can lock"....(???) Experience.....gather it, learn from it, love it. ....and some technical expertise might not hurt either... ericm I hate to even ask this but are there any videos on this? I have heard about this for years but never seen it and want to learn more and hopefully not experience it Thanks Link to comment Share on other sites More sharing options...
Mark Gale Posted February 10, 2012 Share Posted February 10, 2012 (edited) I hate to use the word "experience", but....you are mistaken. I can demonstrate, by EXPERIENCE, that firing pin momentum can be and has been responsible for "slam fire" events in AR pattern guns. It is decoupled from bolt momentum, which, by the way, is not "stopped by the chambered cartridge before it can lock"....(???) Experience.....gather it, learn from it, love it. ....and some technical expertise might not hurt either... ericm I would love to see it demonstrated. As for experience, I guess I don't have enough. Mark Gale Armorer / Machinist Specialized Armament (480) 940-7397 Edited February 10, 2012 by Mark Gale Link to comment Share on other sites More sharing options...
gerritm Posted February 10, 2012 Share Posted February 10, 2012 What buffer are you using? Sometimes a heavier spring plus a heavy or H2 buffer is to much. Won't cycle. gerritm Link to comment Share on other sites More sharing options...
ericm Posted February 10, 2012 Share Posted February 10, 2012 I hate to use the word "experience", but....you are mistaken. I can demonstrate, by EXPERIENCE, that firing pin momentum can be and has been responsible for "slam fire" events in AR pattern guns. It is decoupled from bolt momentum, which, by the way, is not "stopped by the chambered cartridge before it can lock"....(???) Experience.....gather it, learn from it, love it. ....and some technical expertise might not hurt either... ericm I would love to see it demonstrated. As for experience, I guess I don't have enough. Mark Gale Armorer / Machinist Specialized Armament (480) 940-7397 Please start a new Slamfire thread in this forum, stating your original premise, and let the OP get his problem answered.... I'm sure many with experience and expertise will weigh in... Eric Miller, P.E. B.S.M.E MEA Engineering, LLC ericm Link to comment Share on other sites More sharing options...
mike cyrwus Posted February 10, 2012 Share Posted February 10, 2012 (edited) Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. little gnomes that live in my BCG use hammers to pre-dent my primers, so that when the fp does hit it, they go off. Its an option on some newer rifles. Edited February 10, 2012 by mike cyrwus Link to comment Share on other sites More sharing options...
DocMedic Posted February 10, 2012 Author Share Posted February 10, 2012 I am using a JP Carbine buffer spring in an UBR stock with no problems. I am away from home so I can't measure, but I am sure if you give JP a call they will help with the situation. UBR setup is what I'm currently running, do you know what Buffer you are using? is it a Standard or a H+? I'll give a call to jp once I get out of work. Link to comment Share on other sites More sharing options...
Colodrew Posted February 10, 2012 Share Posted February 10, 2012 Curtis, I just changed from a rifle length to carbine length JP buffer and spring and had zero problems on my CTR-02. My buffer spring measures 11.25". Also,I think my carbine buffer is standard. I do know that it weighs the same or 1/4 oz. less than my low mass JP Buffer (rifle length)because I weighed them before I installed it. My adjustable gas block is set almost exactly per JP's instructions maybe 1/4 turn more. I am also running the low mass carrier. Good luck. Link to comment Share on other sites More sharing options...
Jesse Tischauser Posted February 11, 2012 Share Posted February 11, 2012 Um, they don't work too well in the carbine version. While they "say" it is plus 10%, it is more like plus 25% based on what I can tell. When you do finally get it to run, you will need a Titanium firing pin to keep it from slam firing also. Mine is 11.5" long. I hate to use the word impossible but... It is mechanically impossible for an AR-15 to slam fire as a result of firing pin momentum. The firing pin is not long enough to protrude through the breach face until the bolt is locked. The forward momentum of the bolt is stopped by the chambered cartridge before it can lock. little gnomes that live in my BCG use hammers to pre-dent my primers, so that when the fp does hit it, they go off. Its an option on some newer rifles. I use the new Wolf predented primers. In case the gnomes go on strike. Link to comment Share on other sites More sharing options...
diversmith Posted February 11, 2012 Share Posted February 11, 2012 I am using a JP Carbine buffer spring in an UBR stock with no problems. I am away from home so I can't measure, but I am sure if you give JP a call they will help with the situation. I am using this set-up with a standard carbine weight buffer....zero issues thru several thousand rounds of milspec and commercial ammo. You need to call JP Link to comment Share on other sites More sharing options...
jobob Posted February 14, 2012 Share Posted February 14, 2012 I have these springs in two carbines. A Bushmaster carbine, and a build with a BM upper on a Cavalry Arms lower. Both have the Spikes heavy buffer and both function very well. JP will help you out if you call. They are top flight folks. Link to comment Share on other sites More sharing options...
LPatterson Posted February 14, 2012 Share Posted February 14, 2012 I hate to use the word "experience", but....you are mistaken. I can demonstrate, by EXPERIENCE, that firing pin momentum can be and has been responsible for "slam fire" events in AR pattern guns. It is decoupled from bolt momentum, which, by the way, is not "stopped by the chambered cartridge before it can lock"....(???) Experience.....gather it, learn from it, love it. ....and some technical expertise might not hurt either... ericm I would love to see it demonstrated. As for experience, I guess I don't have enough. Mark Gale Armorer / Machinist Specialized Armament (480) 940-7397 Please start a new Slamfire thread in this forum, stating your original premise, and let the OP get his problem answered.... I'm sure many with experience and expertise will weigh in... Eric Miller, P.E. B.S.M.E MEA Engineering, LLC ericm Gentlemen and I use that term loosely, it is a mechanical piece of equipment and MR. MURPHY can make it do just about anything he wants it to. I am a dumb high school drop out but during training to go to SEA (damn was it really 45 years ago)the M16 I was given did it several times before they took it away from me. Link to comment Share on other sites More sharing options...
bpipe95 Posted February 14, 2012 Share Posted February 14, 2012 I run JP and Tubbs springs in ALL of my AR's carbines and rifles. I have never had one slamfire. Brad P Some peckerwood that loves black rifles.... Link to comment Share on other sites More sharing options...
RWF Posted February 14, 2012 Share Posted February 14, 2012 I run JP and Tubbs springs in ALL of my AR's carbines and rifles. I have never had one slamfire. +1 did the gun okay before you changed the spring? any chance the gas block may have come loose or been bumped? Link to comment Share on other sites More sharing options...
fastarget Posted February 14, 2012 Share Posted February 14, 2012 Should you change your stock rifle spring (ismi), if you replace the stock components with JP light buffer and lightened BCG? Link to comment Share on other sites More sharing options...
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