MD arms drum breakin

[weissfe 3]

Saiga 12 with a Tac 47 Autoplug....

 

I've been running the Saiga with Wally World bulk pack Federal and Remington no problem. Buckshot and Slugs work great too using the AGP 10 round mags.

 

So I have family over, decided to break out the 20 rnd Drum.

 

Brand new, I fitted it but never used it.

 

Stick in the Birdshot lots of FTE. Almost single shot.

 

Drum ran all the high power stuff just fine no FTE.

 

I didn't want to mess with my Autoplug settings since it's working great with all ammo with the AGP mags.

 

Is there something I can do to break in the drum or do I have to mess with the spring settings?

 

Also, if I mess with the springs so it runs the low power stuff is that going to break it running the high power ammo?

 

Thanks!

[bigcec1 72]

change the spring tension I would try turning it back mabie half a rotation and it won't hurt any thing remove the back cover once it's open with out ammo in it of course you should turn the enternal part of the drum where the shells go I forget the name of it to loosen tension on the stopper once you have tension removed take out the stopper it should pull out towards you slowly by hand rotate the internal drum half a rotation now reinstall the stopper mark were you pull it from so you know about how much is half then put the cover back on fill half with low and high shot test

[bigcec1 72]

Also do you have the bolt and carrier polished that might help I had the same issue with both drums instead of adjusting I just polished the bolt and carrier

[fauxknight 30]

The drum has much higher spring tension than your mags, this means with it inserted the rounds are pressing up harder against your bolt causing more friction and robbing you of some cycling power. Some things that will help:

 

1. Less spring tension - loosen the spring in the drum.

2. Less friction - polish bolt and bolt carrier.

3. More gas pressure - tighten your autoplug a little more.

[evlblkwpnz 3,418]

From plenty of experience with these drums, the drum is fine at the factory setting of three turns of spring tension. They tend to have trouble keeping up with rapid fire when you reduce tension The weapon is what needs work. I know that it isn't what you want to hear, but you may need some reprofiling of the hammer and carrier bottom, and possibly some port work.

 

First, try it with the factory plug on setting 2 before you do anything else. This can give you an idea of how close you are to running well with the TAC plug and you can rework/modify accordingly. Report back with the results, I am interested in what you find.

 

ETA: a little graphite (like the specific kind that comes with the AR15 Betamags) on the bearing surfaces inside the drum adds a little benefit. After being 'cycled' a few times, the drums do tend to loosen up some.

Edited May 3, 2011 by evlblkwpnz

[tbizzle 18]

Try installing a MD arms booster puck. It did wonders to help my gun cycle the cheap stuff with drum. Before = no cycle without FTE. After = no problema

[weissfe 3]

I'll try the factory plug at 2, good idea. It's awful close to running with Wally World in the Drum. My family were the ones with all the FTE's.

 

I was able to firmly shoulder it and get it working (mostly).

 

Might just need another tweak on the Auto plug.

 

Think I'll try the booster puck next if that doesn't work.

Edited May 3, 2011 by Aspect

[TwentyNizzo 66]

In my experience, 2.25 turns of spring tension on the MD arms drum is equivalent to the spring tension of a factory 8 round mag in terms of not creating so much tension as to induce fte. After reprofiling and polishing the carrier and bolt, the gun cycles Federal blue box game load 1oz ($4.67/25 stuff at walmart) as fast as you can dump the drum with the spring set to 2.5 turns. I could increase the tension back to 3 turns if I wanted to but I only shoot birdshot out out of the drum so I really have no need.

Edited May 3, 2011 by TwentyNizzo

[poolingmyignorance 2,191]

Do the polish job, it's easy, it's cheap, and you'll FEEL a diffrence when your done just hand cylcling. The polish and Vplug are the only modifications to my stock s12 and it runs all the wall world and federal you can feed it. If you read the MDArm info on the drum they recommend NOT changing the standard 3 turns because it will be insufficant for heavy loads. You don't really want to have a mag thats only good for light loads, and ones that are only good for high ones do you?

I did my initial polish job with just some mill scale jewler files and 180grit sand paper to get it to run the Federal perfectly from the hip, since then i've gone back with a buffing wheel and got it to run the wally world junk fine too. Read the how to on the bolt, it's cheap it's effective and it's easy. Then start looking at your gas system. Good luck.

 

 

[Paulyski 2,227]

Many are just referring to it as "polishing". There's a whole lot more to it than that.

 

It's a complete re-profile to smoothen the entire action during the feeding & extraction cycle then polish if one want's optimal results.

 

I've lost count of how many light sandings & 2nd rate polishing jobs that I've reworked. There's actually 3 on my bench in the batch of sets that I'm doing right now.

 

If one want's optimal performance with low recoil or target loads, one must change the whole profile & if one changes the whole profile, it's highly advisable that they know what they're doing, otherwise, in the best case scenerio, all is for naught. On the other end of the spectrum, if one treats the wrong areas the wrong way, or lacks the ability to measure what they're doing, they just royally screwed their gun, so with that in mind, it's better to err on the side of caution & do the light sanding & second rate polish, then still avoid the lighter rounds.

 

But do yourself a favor & keep the drum at the high brass spring setting just in case you need it to work with real ammo in an emergency.