Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
11/11/2016 8:03:55 PM EDT
I thought there was a section here about these but couldn't find it so here goes.

I have had this Bump Fire stock on my AR15 for a couple years now and it has worked flawlessly until a couple months ago. The problem I am having is that with reloads that I have used before now will not dump a 30 round mag all at once, I'll get maybe 3 or 4 rounds and then it stops, another 3 or 4 rounds and stops again. These reloads are the same powder, amount, bullet and primer that worked with no problems before. When it first started happening I figured well maybe I was on the low end of the load and decided to try upping the powder load a few 10ths and it worked again. Well, about a week later it started doing the same thing. Just to make sure it wasn't me I tried some factory LC XM193 rounds and went through 3 boxes without a hiccup. So now I'm wondering why this keeps happening with my reloads. Could it be that something is wearing out requiring a hotter load for the recoil to be enough to bump? Before you ask, my reloads are consistent from batch to batch with the only difference being a different bottle of the same powder.

Any ideas out there of what may be happening?
11/11/2016 8:26:50 PM EDT
[#1]
First identify why the bump is stopping. Are you getting hammer follow? This would be from pushing forward to hard. Is it that the trigger is not resetting (the hammer is still on the disconnected and you can let off and pull and then it fires)? This is from also pushing forward to hard and maybe not enough recoil. I can't bump more than a couple rounds if I use a vfg. It works best for me to just use a regular handguard.
11/11/2016 9:00:12 PM EDT
[#2]
Honestly, I'm pretty sure everything is doing what it's suppose to, trigger resets and everything else you mentioned. Not to brag but I consider myself an expert on shooting the bump fire with that being I know how much to push, how little to have the stock on my shoulder. I can choose to shoot off 3, 6, 10 rounds at a time or a whole mag. The rifle is set up really nice and I can have someone who has never shot a bump fire before shooting of a whole mag once I show them how to do it. I really think it has something to do with the reloads. To give you an idea, I can take 4 or 5 mags, some with reloads, some with factory loads and use them randomly and the factory loaded ones will work perfectly and then reloads will fail.

I guess what I'm getting at is that from what I've told you, that my reloads are the problem but the same reloads I used 2 weeks ago worked perfectly then they don't until I up the powder load again. I also thought well maybe the gun is getting dirty so I started bringing my cleaning stuff with me and that did not help one bit. My only thought is either maybe a gas problem or maybe the buffer spring is wearing out, I just don't know. I guess I could take a spring from another AR and try that.
11/11/2016 9:12:16 PM EDT
[#3]
I have never been able to use reloads in my bumpfire system, it has to be factory ammo and then I use it is another, I don't know why, but I don't use reloads in my M16's either because they won't cycle correctly.
11/11/2016 9:24:26 PM EDT
[#4]
I could understand if reloads don't work but they have for almost 2 years without one problem, just only in the past 2 months this occurred. I can't keep upping the powder load because as anyone knows, I'll reach the max.
11/11/2016 11:56:08 PM EDT
[#5]
Quote History
Quoted:
I could understand if reloads don't work but they have for almost 2 years without one problem, just only in the past 2 months this occurred. I can't keep upping the powder load because as anyone knows, I'll reach the max.
View Quote

How fast of powder are you using? Relatively. I've been out of reloading a long time, but I know faster powder gives you a snappy recoil and slower powder gives you a slow roll recoil like a black powder gun. Whatevr you're using, try the opposite extreme of burn rates.
11/12/2016 12:30:43 AM EDT
[#6]
I've been using 4064, Tac, CFE 223, Varget, AR Comp, BL-C(2) all which have worked before which Tac and 4064 is what I use mostly. Used most common brands of primers and usually LC brass and 55gr FMJ B/T bullets. I believe TAC is the fastest one I have used so far.
11/12/2016 12:43:08 AM EDT
[#7]
How many rounds on your recoil spring and barrel?



Done a gas leak check?




Tried bumping with other lighter loaded .223 factory ammunition?




These reloads are locking the mag back every time?




Have you run the reloads over a chronograph to see how fast they are?
11/12/2016 3:34:58 AM EDT
[#8]
Quote History
Quoted:
How many rounds on your recoil spring and barrel?  Around 500 rounds

Done a gas leak check?  No


Tried bumping with other lighter loaded .223 factory ammunition? Yes, they will not work


These reloads are locking the mag back every time? Yes, they work fine other than what I've said


Have you run the reloads over a chronograph to see how fast they are?  No, I don't have a chrono but I can use my friends.
View Quote

11/12/2016 10:32:49 PM EDT
[#9]
Are you using a VFG? If so, don't.
Are you using a heavy buffer or other set up to reduce recoil? If so go back to a regular CAR buffer and spring. You want a good recoil impulse when bumping.

I have a feeling that you are either pushing forward to hard (happens with a VFG) and/or you're not getting enough recoil to slide back far enough to reset the trigger.
11/12/2016 10:36:17 PM EDT
[#10]
Is it cold out? Was it warmer on previous trips when you were bump firing?
11/12/2016 11:51:04 PM EDT
[#11]
How many times have you reloaded your brass?
11/13/2016 5:32:41 PM EDT
[#12]
Sorry it took me awhile to get back, I've been loading up some more test rounds and just got back from the range. The new loads worked great, then I tried some of my older loads that have been failing to work and they worked this time.

At first I was thinking maybe because it's been colder in the mornings and that maybe the powders I'm using are temp sensitive but then I think I found the problem. Since the mornings have been colder I have been wearing a heavy coat and I'm not getting the bump off my shoulder because of the thick coat. Today I went out later in the day and it was warmer so I just had on a thin jacket. So my next experiment will be the next time I am out with my coat on, I'll try it again and if I can't get it to bump, I'll take my coat off and try it again. Oh, I will do this using my older loads that started giving me the problem.

AASG, I do not have a VFG and I also have a regular carbine buffer/weight and spring.

bricklayer40, they are all once fired brass.
AR Sponsor