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1/22/2020 12:12:56 PM
Posted: 1/18/2015 9:11:16 PM EST
I know I saw a post about this probably over a year ago. Why does this happen and does anybody make a better/stronger bolt catch. It almost looked like pot metal the way it cracked.

I am running a DDLES colt style lower with an 8.5" CMMG complete upper and the buffer is a spikes ST-9 made for a 9mm AR and a extra power wolff spring.

Thanks!
Link Posted: 1/18/2015 9:24:11 PM EST
Originally Posted By armored223:
I know I saw a post about this probably over a year ago. Why does this happen and does anybody make a better/stronger bolt catch. It almost looked like pot metal the way it cracked.

I am running a DDLES colt style lower with an 8.5" CMMG complete upper and the buffer is a spikes ST-9 made for a 9mm AR and a extra power wolff spring.

Thanks!
View Quote


Here is a post I created a few weeks ago. I think I damaged my bolt catch when I used a carbine buffer and spring right after the build.....was pretty excited to try out the build and I didn't pay close enough attention to the various buffer sizes/weights: http://www.ar15.com/forums/t_3_15/664720_JP_9mm_Silent_Spring_and_Broken_Bolt_Catch.html
Link Posted: 1/18/2015 9:36:48 PM EST
[Last Edit: 1/18/2015 9:42:44 PM EST by rgrprib]
It is caused the heavier, 9mm bolt that builds up more inertia, and will break all bolt catches, eventually.

There are two or three options to prevent this from happening:

1. Spikes make a spacer that is placed in the buffer tube/reciever extension .



2. Ther are a few manufactuers that make a heavy, 9mm buffer that also takes up the bolt travel distance.




3. Place about six U.S. quarters into the buffer tube/reciever extension, then the spring and buffer.
Sorry, forgot to mention the JP sytem....I've got their olt and silent capture set on order, and will report once I get a chance to install and put tit through its paces.


Link Posted: 1/18/2015 9:53:36 PM EST
I used quarter in my buffer tube as well.
Link Posted: 1/18/2015 9:53:48 PM EST
The buffer I have is the Sikes ST-9x....This is the longer heavier buffer already.

Does anyone make a stronger aluminum or titanium bolt catch?
Link Posted: 1/18/2015 9:55:52 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By armored223:
The buffer I have is the Sikes ST-9x....This is the longer heavier buffer already.

Does anyone make a stronger aluminum or titanium bolt catch?
View Quote



Have you checked to see how far past the bolt catch the bolt face is going? If it's going to far it will build up the speed and break it. You may have to add some quarters.
Link Posted: 1/18/2015 9:58:47 PM EST
You shouldnt have to worry about bolt catches breaking wth the ST-9.

I cant say I know of bolt catches made of other materials though.

Link Posted: 1/18/2015 10:04:38 PM EST
[Last Edit: 1/18/2015 10:36:14 PM EST by seattlite]
I just checked my JP 9mm Silent Spring...the bolt stops at about 0.138" past the bolt catch. This is with me pulling on the charging handle all the way to the back till it stops.
Link Posted: 1/18/2015 10:28:34 PM EST
How would you know how far back its going when its fired?
Link Posted: 1/18/2015 11:36:23 PM EST
Easy and most shootable solution: disable the bolt-hold-open-on-empty feature. Let the bolt close on an empty chamber. Just use the BHO manually. That is how my AR15/9 is set up (with a Hahn mag block) and it works great.
Link Posted: 1/19/2015 8:52:48 AM EST
The CMMG catch I had was taller than the RRA I am running now. Don't know if this has anything to do with it but thought I would share. I'm curious also as to the gap in bolt face to bolt catch with charging handle pulled rearward. Over travel was my first thought.
Link Posted: 1/19/2015 7:22:15 PM EST
it is a CMMG lower parts kit

But I am still not sure what it matters with the bolt pulled back with the charging handle means. Doesn't the travel or over-travel of the bolt depend on how much buffer and spring there is to absorb it?
Link Posted: 1/19/2015 10:24:15 PM EST
I us a Heavy Buffers 45 buffer & Wolf extra power spring with my 9MM & 40 S&W uppers & have never broken a bolt catch.
Link Posted: 1/19/2015 11:46:58 PM EST
[Last Edit: 1/20/2015 12:13:48 AM EST by beanfield33]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By armored223:
The buffer I have is the Sikes ST-9x....This is the longer heavier buffer already.

Does anyone make a stronger aluminum or titanium bolt catch?
View Quote

Your standard bolt catch should be hardened steel... you definitely don't want aluminum (softer than steel) and I'm not so sure you're better off with Ti either, but that would really depend on the specific alloy you're comparing.

Is this happening repeatedly or just once? Since you're using an st-9x, it should lessen the force compared to a car length buffer. I'd replace the catch and not worry about it unless it continues to happen. It may have just been a faulty part (I.E. missed the hardening process).
Link Posted: 1/20/2015 12:07:34 AM EST
This was the first time it broke but only 100-150rd in. I will replace it and see if it was just a fluke. Thanks for the info.
Link Posted: 1/20/2015 7:35:05 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By armored223:
This was the first time it broke but only 100-150rd in. I will replace it and see if it was just a fluke. Thanks for the info.
View Quote


I agree that its most likely a fluke (I hope for all of us QC10 guys). Just for your info, I have a QC10 CLT9MM lower that I've run over 500 rounds through (I know its not a lot, but its pretty new). I used an RRA LPK (standard Mil-Spec parts), a Slash 9Q-T buffer and both a Wolff XP spring and a standard carbine spring. I am shooting unsuppressed (suppressor still in jail) and found that the rifle would not cycle with the full 9Q-T weight and XP spring. Keeping the full buffer weight with a standard buffer spring fixed this. Making the buffer lighter (going to the 9Q weight instead of the full 9Q-T weight) with the XP spring also fixed the issue. I elected to stay with the full 9Q-T buffer weight and have a standard carbine buffer spring in it now. No issues at all. It was the worst shooting Remington UMC 147gr ammo, but with the current setup, that ammo cycles fine. I have not had any issues with the bolt catch (knock on wood). Last round hold open works every time now with the buffer/spring setup I have now.

I don't have a way to measure how much space is between the bolt face and catch when I pull the charging handle all the way back, but when I do that, manually holding the bolt catch, the bolt doesn't lock back until I'm at the very end of the charging handle travel. I'm sure there is a little space there, but its sure hard to tell how much. It has to be a very small amount. If you can perceive additional travel of your charging handle after the bolt locks back, you might try that trick of putting a quarter in the buffer tube. If I do that, I cannot get the bolt to lock back at the absolute end of the charging handle travel.
Link Posted: 1/20/2015 9:22:25 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By wpeschel:
I used quarter in my buffer tube as well.
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It's enough to get a soda when you're strapped at the range.
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