Maxim RDB failures?

[bigdawgbeav]

So last weekend I was running my AR-V at the PA State Steel Challenge Championship and something odd was happening.  First shot, first string I was getting stovepipes.  Cleared the malfunction and continued.  This did not happen on subsequent strings.  Next stage, same thing happened.  

 

I thought it might be the first mag, but disproved that by starting with a different mag, then another.  Same thing kept happening.  This was until my 2nd to last stage where it locked up completely, but that was because this time the stovepiped brass got jammed in the receiver and the bolt was dragging over the top of the brass. (had to finish the last 2 stages shooting my PCCI in PCCO)

 

I wish I had some pictures, but i'm looking for ideas as to why (prior to the lock-up) the first shot was stovepiping and everything else was fine.  I did think that maybe I was riding the charging handle and the bolt wasn't fully engaged, but I was making sure that the bolt was closed on the chamber.  I have not had this problem before...

[zzt]

With ten rounds plus in the mag the upward push is significant.  You are running a Superfeed barrel.  They have a tight chamber.  The Maxim delays opening so a lot of the pressure had already left the 5 1/4" barrel.  The gun 'dries out' a tad between strings.  The first round deposits more goop in the action and it is slicker again.

 

Maxim does not yet offer different recoil springs.  So, do one, two or all of three things.  First, put a line on oil along the top of the top round in the bag- old bullseye trick.  Two, take the weight out of the bolt.  Three, up the charge in your reloads.

[Joedirt199]

Were these fired brass or live roubd trying to feed and jamming up. I have the same setup and would get a near last round jam where the round would miss the chamber and jam in the roof of the receiver. Thought it was the mag but it didn't on both my Magpul and PSA mags. I fit a delrin spacer to short stroke the bolt, no need to run 223 length in a 9mm. I need more rounds through it but it runs well now. 

[bigdawgbeav]

15 hours ago, zzt said:

With ten rounds plus in the mag the upward push is significant.  You are running a Superfeed barrel.  They have a tight chamber.  The Maxim delays opening so a lot of the pressure had already left the 5 1/4" barrel.  The gun 'dries out' a tad between strings.  The first round deposits more goop in the action and it is slicker again.

 

Maxim does not yet offer different recoil springs.  So, do one, two or all of three things.  First, put a line on oil along the top of the top round in the bag- old bullseye trick.  Two, take the weight out of the bolt.  Three, up the charge in your reloads.

I can try the oil, the weight is already out or else it wouldn't function at all.  As for the light loads: I've run these rounds before with no issues.  I'll have to spend some time at the range to figure this out.

[mrvip27]

when you pull back on the bolt, how far back does it go? i found out the AR-v (which i run) has a fine line of being too short stroked depending on the buffer. I know the length on the buffer tube is critical for this RDB and some tubes vary slightly. Some people had to move the buffer tube out a turn or two. even with the 5020ss i run in an a5 tube..if i short stroke it too much like even .100-.200 it wont have enough for ejection.

 

Have you had issues before you changed to the RDB? Or only since this buffer?

 

Also, have you really cleaned the chamber lately? I know some build up there can make it hard to extract the round and it can get stuck a bit. or cause weird extraction. I run a superfeed as well. I was having issues with ejecting the last round on unload and show clear that my charging handle would get stuck trying to pull the round out.

 

Also, have you cleaned under the extractor lately?

 

Ejector still aligned in a good place with the bolt?

 

Are the rounds too "soft" of a PF to overcome the strength of the RDB? especially after you run some rounds towards the end of a match?

 

I know short stroking is the cool thing these days but even Aaron Brekke has said at some point reliability over the course of a match makes more sense than the slight benefit of a short stroke spacer, etc.

 

PS....have you checked your firing pin spring? I was still able to use my AR-V but i was getting all sorts of issues during the match...found out my spring was broken.. replaced it and problems went away.

Edited May 24 by mrvip27

[bigdawgbeav]

when you pull back on the bolt, how far back does it go? - It isn't short-stroked.  When I pull back it passes the ejector and LRBHO.  This is with a carbine buffer tube. 

 

Have you had issues before you changed to the RDB? Or only since this buffer? - This is my 2nd RDB.  The first one I had no issues with regarding ammo choices.  I swapped to the new Taccom system and then sold the original RDB.  I realized I should have kept it as a backup and bought one off another shooter locally.  It was this "new" one that has issues.

 

Also, have you really cleaned the chamber lately? - I have cleaned it, and have never had any extraction issues (clean or dirty).  Did I clean it before this match, no.  But that is mostly because the AR-V was only run a couple of times prior to this.

 

Also, have you cleaned under the extractor lately?  Ejector still aligned in a good place with the bolt? - yes, again, the issue was only the first round of the first string.  all others strings were fine.

 

Are the rounds too "soft" of a PF to overcome the strength of the RDB? - I am running 100PF loads for Steel Challenge, but the previous RDB handled them like a champ.  
https://rumble.com/v3pbhpt-maxim-defense-roller-delayed-buffer-test.html (The Taccom Air Buffer in the video is the regular system, not the Enhanced)

 

have you checked your firing pin spring? - I have not, but other than the first round, first string stovepipe there were no other issues until the 2nd-to-last stage when the FTE ended up under the bolt in that little cutout in the AR-V lower

 

Thank you for the questions/insight. I have put my Taccom Enhanced 3-Stage system back in and it runs great with low PF ammo.  Recoil impulse is not better or worse, just different. 

 

As I am less than 2 weeks away from another major (Area 5 SC) I'm keeping the system as is and will test after.  I'm going to keep the A5 tube on and get a spacer for behind if I drop the Maxim back in.

 

 

 

Edited May 28 by bigdawgbeav

[mrvip27]

14 hours ago, bigdawgbeav said:

when you pull back on the bolt, how far back does it go? - It isn't short-stroked.  When I pull back it passes the ejector and LRBHO.  This is with a carbine buffer tube. 

 

Have you had issues before you changed to the RDB? Or only since this buffer? - This is my 2nd RDB.  The first one I had no issues with regarding ammo choices.  I swapped to the new Taccom system and then sold the original RDB.  I realized I should have kept it as a backup and bought one off another shooter locally.  It was this "new" one that has issues.

 

Also, have you really cleaned the chamber lately? - I have cleaned it, and have never had any extraction issues (clean or dirty).  Did I clean it before this match, no.  But that is mostly because the AR-V was only run a couple of times prior to this.

 

Also, have you cleaned under the extractor lately?  Ejector still aligned in a good place with the bolt? - yes, again, the issue was only the first round of the first string.  all others strings were fine.

 

Are the rounds too "soft" of a PF to overcome the strength of the RDB? - I am running 100PF loads for Steel Challenge, but the previous RDB handled them like a champ.  
https://rumble.com/v3pbhpt-maxim-defense-roller-delayed-buffer-test.html (The Taccom Air Buffer in the video is the regular system, not the Enhanced)

 

have you checked your firing pin spring? - I have not, but other than the first round, first string stovepipe there were no other issues until the 2nd-to-last stage when the FTE ended up under the bolt in that little cutout in the AR-V lower

 

Thank you for the questions/insight. I have put my Taccom Enhanced 3-Stage system back in and it runs great with low PF ammo.  Recoil impulse is not better or worse, just different. 

 

As I am less than 2 weeks away from another major (Area 5 SC) I'm keeping the system as is and will test after.  I'm going to keep the A5 tube on and get a spacer for behind if I drop the Maxim back in.

 

 

 

 

You are very welcome. I have seldom had any real issues with my AR-V.

 

Seems it is running fine for you with the different buffer. Interesting. Wonder the issue?

 

Ps. have you checked for loose screws on the feedramp? One of mine came loose finally after many many rounds. You could move the feedramp around a bit.

Edited May 29 by mrvip27

[bigdawgbeav]

10 hours ago, mrvip27 said:

Ps. have you checked for loose screws on the feedramp? One of mine came loose finally after many many rounds. You could move the feedramp around a bit.

I did... I had those come loose last year at one point.  When I opened it up last i double checked the ramp was tight.  I do that every time I open it just to make sure.

[mrvip27]

On 5/29/2024 at 6:36 AM, bigdawgbeav said:

I did... I had those come loose last year at one point.  When I opened it up last i double checked the ramp was tight.  I do that every time I open it just to make sure.

 

well let us know what you find out!

[WildPete]

I just got the Taccom wave spring buffer kit. Looking forward to testing it out. I don't reload but will try it out with 110 PF ammo and 88 PF ammo. 

 

Glad to see you figured out your problem. Good luck at At Area 5. I can't make it this year so it's Area 8 for me.

[bigdawgbeav]

11 hours ago, WildPete said:

I just got the Taccom wave spring buffer kit. Looking forward to testing it out. I don't reload but will try it out with 110 PF ammo and 88 PF ammo. 

 

Glad to see you figured out your problem. Good luck at At Area 5. I can't make it this year so it's Area 8 for me.

I actually haven't figured it out yet.  But with a major a week away it's probably a smart idea to go with what works and not screw around for right now.

[LowSpeedHighDrag]

On 5/30/2024 at 8:32 PM, WildPete said:

I just got the Taccom wave spring buffer kit. Looking forward to testing it out. I don't reload but will try it out with 110 PF ammo and 88 PF ammo. 

 

Got one, tried it, and put the Maxim back in.

[WildPete]

1 hour ago, LowSpeedHighDrag said:

Got one, tried it, and put the Maxim back in.

 

Off the shelf ammo or match-specific loaded ammo?

[LowSpeedHighDrag]

On 6/1/2024 at 10:48 AM, WildPete said:

 

Off the shelf ammo or match-specific loaded ammo?

Match-specific load.  160 gr. Blue Bullets over 3.0 gr. N320.

 

I'm not saying that the Taccom buffer was bad, just that I preferred the Maxim.  Haven't compared it to buffers other than the Maxim.  So far I like the delayed opening buffer type, and the Maxim is one that's just GTG and doesn't need a lot of fiddling to make work.