Springfield XD Forum banner

1 - 20 of 33 Posts

·
Registered
Joined
·
19,505 Posts
Discussion Starter #1
I am thinking about picking up some 20 round mags, and see they have straight and curved examples out there.
Stoner was fine with a straight mag at 20 round capacity. It wasn't until mags got larger that the curve came to be.

Is the difference just in tooling that manufacturers have available? or are their real performance differences between these two?

Would no-tilt followers come into play?
 

·
Registered
Joined
·
29,541 Posts
My 20 rounders are all 1st gen PMags...besides a couple ancient Colt marked 20’s from the Vietnam era that I don’t use.

The PMags are straight, and function fine. I like them if I’m gonna run off a bench, or prone.
 

·
Registered
Joined
·
19,505 Posts
Discussion Starter #3
My 20 rounders are all 1st gen PMags...besides a couple ancient Colt marked 20’s from the Vietnam era that I don’t use.

The PMags are straight, and function fine. I like them if I’m gonna run off a bench, or prone.
Looks like the gen 3s looked curved from the pictures I've seen. Wonder why they changed?
 

·
Registered
Joined
·
1,235 Posts
I've got gen 2 and 3 20rd pmags.

Not for certain what they changed, but my gen 2's don't lock the bolt back on empty as reliably as the gen 3.

Both feed just fine.
 

·
Registered
Joined
·
19,918 Posts
I've got a couple M3 20 round Pmags that run fine with .300BLK.

I'll assume the mold was cheaper to tool up with the slight curve....
 

·
Registered
Joined
·
7,001 Posts
I've got gen 2 and 3 20rd pmags.

Not for certain what they changed, but my gen 2's don't lock the bolt back on empty as reliably as the gen 3.

Both feed just fine.
IIRC, that was a known problem on some of the Gen M2 20-rounders. I can't quite remember what was the underlying cause and my Google-Fu is failing me, but there actually was one (I found some of Will Larsen's old posts that alluded to the defect, but none addressed it specifically). Also according to Magpul, there isn't a way to truly implement an anti-tilt follower with their straight-bodied 20-rounders, which was why they went with curved for the Gen M3 20s as well.

Some of the really early Gen M3 20-rounders also had a tolerance stacking issue that affected the force that was needed to seat a fully loaded mag on a closed-bolt (so that in affected magazines, with certain ammo, the second round could nose-up alongside the first), but Magpul quickly remedied that one.
 

·
Registered
Joined
·
19,505 Posts
Discussion Starter #8
IIRC, that was a known problem on some of the Gen M2 20-rounders. I can't quite remember what was the underlying cause and my Google-Fu is failing me, but there actually was one (I found some of Will Larsen's old posts that alluded to the defect, but none addressed it specifically). Also according to Magpul, there isn't a way to truly implement an anti-tilt follower with their straight-bodied 20-rounders, which was why they went with curved for the Gen M3 20s as well.

Some of the really early Gen M3 20-rounders also had a tolerance stacking issue that affected the force that was needed to seat a fully loaded mag on a closed-bolt (so that in affected magazines, with certain ammo, the second round could nose-up alongside the first), but Magpul quickly remedied that one.
this is what I was thinking. with a straight body, the follower's tilt should change depending on how many rounds are in the mag to account for the taper..
 

·
Premium Member
Joined
·
126,810 Posts
At the gun show I visited Saturday, a guy had a table with Vietnam era mags. Several were the 20-round variety. Since that is what I used on both my combat tours 50 years ago, I thought I would pick up a few. I asked, “How much.” He said, “$45 each.” I kept walking.
 

·
Registered
Joined
·
713 Posts
While in Nam (68/69) we always loaded 20 round mags with 18 rounds because 20 often caused jams. This according to our senior NCOs. Have to say I never verified this but my M16 never jammed.

Padraig
 

·
Premium Member
Joined
·
126,810 Posts
While in Nam (68/69) we always loaded 20 round mags with 18 rounds because 20 often caused jams. This according to our senior NCOs. Have to say I never verified this but my M16 never jammed.

Padraig
Where did you serve and what unit were you with?
 

·
Registered
Joined
·
7,036 Posts
I like the okay surefeed 20rd mags in grey or black teflon finish. They have been perfect. I do have a old 20rd straight pmag. Did have a occasional failure to lock open on empty but no feeding problems. The m3 curved 20rd mags have been gtg in my experience.
 

·
Registered
Joined
·
19,918 Posts
If you want the look but don't need them to be Colt or all that jazz, find some D&H or the Okay Surefeed. These are solid.

Okay Surefeed is a supplier of the current isssue 30 rounders.
 

·
Premium Member
Joined
·
3,819 Posts
Try this helpful AR15 mag hint lost in the mists of time. Maybe longer. Take apart. Take OOOO steel wool and polish the insides. Polish the sides of the follower. Slobber up with Break Free or regular LSA. Let dry overnight.

Grab the spring and gently bend the rear coil ends to elongate that side of the spring. Bend the first two or three coils more. Bend the first coil sosss the coil wire rests upon the follower. This increases rear follower spring tension.

This seemed to work on cheapo USGI aluminmiummumm 30 round mags. May not work on 20 round mags. If your mags do not lock back the bolt, CONSIDER slightly trimming the bolt stop spring. Go slow here. Springs cheap.

Hope this helps. Hundreds of builds but long ago and far away. Now old and cooted. Yikes! :)
 

·
Registered
Joined
·
19,505 Posts
Discussion Starter #17
At the gun show I visited Saturday, a guy had a table with Vietnam era mags. Several were the 20-round variety. Since that is what I used on both my combat tours 50 years ago, I thought I would pick up a few. I asked, “How much.” He said, “$45 each.” I kept walking.
I think reproduction waffle mags cost more.
 

·
Registered
Joined
·
423 Posts
For metal aluminum mags, straight mags are the old style Vietnam style mags. You cannot use a anti-tilt follower as these are designed to tilt. If they have good springs, they generally work excellent. I have many thousands of rounds through these and never a jam. For curved 20 rd aluminum mags, they are just shortened 30 rd mags. You can use Magpul anti-tilt 30 rd followers in these curved mags, as its just a shorter 30 rd mag.

For Magpul mags, they sold a straight 20 originally. It was their least reliable magazine that they made/sold, so they went back to the drawing board, and designed the gen 3 20. This mag has a anti-tilt follower and a constant curve geometry. The gen 3 20 rd mag is probably the best built, best designed, and likely most reliable 20 rd mag on the market.

Lancer sells a straight 20 polymer mag. Its constant curve geometry inside and is a nice mag. They do have limiters built into them that make it hard to load 20 rds on a closed bolt. You need to shave this limiter down if you ever plan to load 20 rds into the mag. In fact, that applies to ALL Lancer mags, 20 or 30, they all have pointless limiters built into them that need shaved down. Magpul on the other hand designed their mags properly, which is allowing you the ability to load 1 or 2 extra rounds(dont load extra). This extra space is needed so that you can easily seat a full magazine on a closed bolt.

I have all the mags above. Both styles of metal, and both styles of Magpul. My favorite range mag is the straight aluminum Okay mag, like the original Vietnam style. They just work, and are excellent at the range. For defensive use, I would pick the Magpul gen 3. The magpul straight 20 is likely the worst of the bunch, but I keep them as they are collectible these days and sell for $40 to $50 each.

Everyone should have a few straight Okay 20's in their collection, excellent mags with lots of history and just cool.

Okay Surefeed AR-15 .223 Rem/5.56 20-Round Magazine
 

·
Registered
Joined
·
19,918 Posts
Everyone should have a few straight Okay 20's in their collection, excellent mags with lots of history and just cool.

Okay Surefeed AR-15 .223 Rem/5.56 20-Round Magazine
I keep meaning to pick up some Okay's. For the price, you can't complain. They're a few bucks cheaper than the M3 Magpuls and just as solid. Also, no issues when you get out the 75gr stuff or the heavy sub sonic Blackout loads.
 
1 - 20 of 33 Posts
Top