223 aics

[NJRaised]

Figured I’d ask….

Anyone running an origin 223 in a mpa comp chassis? I got a few mdt mags and they feed awful. Trying to put some work into em.

Anyone have any luck with other mags?

Thanks in advance

 

[Rob01]

Can you adjust mag height in that chassis? I run a TL3, which is basically same bolt face as Origin, in a Manners with mini chassis and the MDT poly mags run great. Wondering if it's a height issue for you. What is the exact feeding issue?

 

[spife7980]

Figure out in what way they are feeding awful and come back to us with something constructive.
Do they pop out early and dont get controlled into the chamber? Do they smash in to the breech prematurely or catch on the feed ramp?
There are a million different ways you could be having issues.
All mags work great in some things.

 

[NJRaised]

I’ve adjusted the height into about every position I can. It seems as though the rounds aren’t sliding into the controlled feed bolt face. Or they’ll jam into the feed ramp. If I position the mag as high up as I can without the lips hitting the bolt, I can get it to feed, but it requires a substantial amount of pressure to feed. I feel like I’m just ramming it into the chamber.

 

[spife7980]

Are you using the metal or polymer mdt mags?
If metal take 5 measurements long the length of the feed lips, front, back, middle and then the in betweens and write them down. Now adjust the feed lips and see if it made it better or worse. If you make it awful you can return to the original and get back to square one.
If metal sand down the inside corner of them as well so that its more of a rounded vs super sharp edge that drags along the case. It will wear in with use and time but a smidge of sanding just gets it kickstarted. Helps them slide out smoother when its not cutting into the brass.

 

[Rob01]

I’ve adjusted the height into about every position I can. It seems as though the rounds aren’t sliding into the controlled feed bolt face. Or they’ll jam into the feed ramp. If I position the mag as high up as I can without the lips hitting the bolt, I can get it to feed, but it requires a substantial amount of pressure to feed. I feel like I’m just ramming it into the chamber.

It's odd that no height makes it work. Are they poly or metal?

You get that same "pressure to feed" the same with a fully loaded mag or just one round in it?

 

[NJRaised]

Poly mdt aics 10 rounders.

Used plenty of metal aics mags for 243 and 308, this is my first adventure in a 223 aics.

The bolt isn’t contacting the mag at all, and the rounds just bind as soon as the bolt hits them. It’s feeds better when it’s a single round out of the mag, but still requires a lot of “force” to chamber a round. Enough to where I’m concerned about deforming bullets

 

[Rob01]

You say to chamber a round. Do you mean to feed it from the mag into the chamber or when it’s actually in the chamber getting the bolt all the way forward?

Can you post a video?

 

[NJRaised]

I’ll post a video when I get home shortly. Thank you guys for the help .

 

[DownhillFromHere]

Are you using the metal or polymer mdt mags?
If metal take 5 measurements long the length of the feed lips, front, back, middle and then the in betweens and write them down. Now adjust the feed lips and see if it made it better or worse. If you make it awful you can return to the original and get back to square one.
If metal sand down the inside corner of them as well so that its more of a rounded vs super sharp edge that drags along the case. It will wear in with use and time but a smidge of sanding just gets it kickstarted. Helps them slide out smoother when its not cutting into the brass.

Spife, MDT "metal" .223 mags aren't all metal. They're about the size - may actually be - .308 metal mags with a polymer insert (red arrow in screen cap below from MDT site) to reduce them to .223 length and feed lip width. I can say from experience that it's difficult to the point of (for me) futility to try to use traditional metal-mag feed lip adjustment techniques on them because the polymer is flexible.
-----
OP, I've used MDT polymer and "metal" .223 mags in:

• Tikka T3X Varmint barreled action in an MDT LSS-XL chassis
• Defiance Deviant barreled action in an MDT ACC chassis
• Terminus Apollo barreled action in MDT ACC chassis

Only the Tikka/LSS-XL rig fed as smoothly as I would expect right out of the gate. The Terminus/ACC rig was stiff and glitchy - perhaps like you're describing, especially with 8-10 rounds in the mag - when it was new, but as metal mags and the new rifle got some break-in time (~800 rounds) things have begun to smooth out.

My Defiance rig is a switch-barrel setup; I have .384" (for .223) and .470" (for 6.5CM) bolts for it. Defiance told me (through Russ at Southern Precision/Bugholes) that the "actual" .223 Deviant action has different feed port dimensions from the standard short action with .470"" bolt (if I remember correctly; "trust but verify"). The rifle feeds superbly with the 6.5CM barrel and MDT 12-round metal mags. It's a little more finicky with the .223 bolt/barrel and polymer or "metal" mags - especially when mags are full to capacity. After I built the Terminus-based .223, I find I don't tinker with the Defiance .223 so much - after a match in a couple of weeks, I'll put the .223 barrel back on and fiddle with it some more...

Bottom line is, I understand your concern / frustration. All I can suggest is try the different suggestions you're getting here, and also give MDT support a call.
-------

 

[spife7980]

Spife, MDT "metal" .223 mags aren't all metal. They're about the size - may actually be - .308 metal mags with a polymer insert (red arrow in screen cap below from MDT site) to reduce them to .223 length and feed lip width. I can say from experience that it's difficult to the point of (for me) futility to try to use traditional metal-mag feed lip adjustment techniques on them because the polymer is flexible.
-----
OP, I've used MDT polymer and "metal" .223 mags in:

• Tikka T3X Varmint barreled action in an MDT LSS-XL chassis
• Defiance Deviant barreled action in an MDT ACC chassis
• Terminus Apollo barreled action in MDT ACC chassis

Only the Tikka/LSS-XL rig fed as smoothly as I would expect right out of the gate. The Terminus/ACC rig was stiff and glitchy - perhaps like you're describing, especially with 8-10 rounds in the mag - when it was new, but as metal mags and the new rifle got some break-in time (~800 rounds) things have begun to smooth out.

My Defiance rig is a switch-barrel setup; I have .384" (for .223) and .470" (for 6.5CM) bolts for it. Defiance told me (through Russ at Southern Precision/Bugholes) that the "actual" .223 Deviant action has different feed port dimensions from the standard short action with .470"" bolt (if I remember correctly; "trust but verify"). The rifle feeds superbly with the 6.5CM barrel and MDT 12-round metal mags. It's a little more finicky with the .223 bolt/barrel and polymer or "metal" mags - especially when mags are full to capacity. After I built the Terminus-based .223, I find I don't tinker with the Defiance .223 so much - after a match in a couple of weeks, I'll put the .223 barrel back on and fiddle with it some more...

Bottom line is, I understand your concern / frustration. All I can suggest is try the different suggestions you're getting here, and also give MDT support a call.
-------

View attachment 7969449

Oh dang, followed in accurate mags foot steps with the liner.
Accurate mag does make two 223 types, one where the plastic doesn’t extend beyond the metal lips and another than does extend beyond like the mdt.
I’m my stuff the non extended lips have fed into a rem 700 from manners mini chassis and a couple mdts flawlessly.
In my ruger American it required the extended lips mags to feed well and failed with the short lips.

I can’t speak to how far the mdt vs accurate mag lips actually are front the fron of the mag but maybe trying a mag with shorter lips that release sooner is what y’all need?

 

[NJRaised]

Having a hard time posting a video…. But this is what I’m looking at at. I have the msg seated as high as possible without the bolt hitting the magazine.

It looks to me like I need to sand the top of the magazine lips down, so that I can see the magazine higher and have more contact between the bolt face and the head of the case.

Let me know what you think. Thanks.

 

[MakeSawdust]

Is the bullet running into the breech face on the barrel? That is the biggest issue I have with mag failures in tl3 and origin actions. Also, the spring in those mags is stiff. The first couple rounds are hard to strip off the stack. The accurate metal mags are much better.

 

[Longrangeprecision762]

I could never get the MDT poly mags to feed and I tried everything. I bought an Accurate mag with the poly liner and it runs flawlessly.

 

[NJRaised]

Doesn’t make a difference whether it’s a single round in the msg or a stack, it just binds up. I may try some accurate mags if this doesn’t pan out .

Didn’t expect 223 aics mags to be this finicky

 

[DownhillFromHere]

A couple of things to try/check:

• Close the bolt. Then insert the magazine. Then try running the bolt. Before my Terminus broke in, I found that inserting a full mag with bolt open caused a misfeed every time. But if I inserted the full mag with bolt closed, the first round would feed just fine (albeit with a lot of pressure because of stiff new mag springs).
• The preceding is probably related to the angle of the magazine in the mag well when the bolt closes. If you have a lot of fore-aft play of the mag when latched in the well, see if you can find the magic angle (you said you've looked for the magic height) and find a way to shim the well to assure that angle.

Good luck.