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View Full Version : Spike's Lower + Magpul PMAG = Tight Fit


mrvash
11-29-2011, 8:37 PM
Both of my Spike's Tactical lower and Magpul 10/30 PMAG are brand new, but the PMAG is really tight when inserted in the magwell, I practically have to slam it in and yank it out to remove it. I have used GI mags 10/20 and 10/30 and they fit fine and drop free when the magazine release/bullet button is used. The same PMAG fits a bit tight in my brother's Spike's lower, but the fitment is ALOT better than mine..

Any advice? Thanks guys..:(

Edit: If it matters, I have a brand new Rock River Arms LPK and Raddlock Gen-X bullet button installed.

Metal Magic
11-29-2011, 9:23 PM
Sounds like a mag catch issue, I would check to be sure you used the spring that came with the raddlock and not the spring that came with the LPK.

lawhite92
11-29-2011, 9:24 PM
Sounds like your mag catch. I have a spikes lower and pmags are a great fit and drop right out when the mag release is hit

hondamanr
11-29-2011, 9:25 PM
i've owned a spikes lower and used it with many pmags without any problems. i'd recommend checking your BB.

lawhite92
11-29-2011, 9:26 PM
I have a raddlock on mine too... Now I have no clue what's going on with yours. Hope some of the Internet kings here will help you out

SureShot241
11-29-2011, 9:27 PM
Just cause I feel like experimenting... put the mag in the freezer for 5 minutes then try. I hear object shrink when cold. If this works then its the mag most likely


I am most likely very wrong, just seeing if my crazy ideas actually work haha

FatalKitty
11-29-2011, 9:28 PM
I've read reports of some folks having to "sand pmags" in order for them to fit their ARs... this may be a tolerance stacking issue (lower and mag both at opposite ends of tolerance spectrum)

good news is... you don't have to worry about looking like a mall ninja flipping your gun around to "eject" the mag.. just pull it out like you're supposed to

RP1911
11-29-2011, 9:30 PM
Try this. Use both O rings that were supplied with the Raddlock. This will move the Raddlock slightly further away from the lower and might help.

cbaer5
11-29-2011, 9:31 PM
try it without the bb installed and the upper off and see where it is rubbing or hitting and you will know if its the bb

I have noticed that pmags very in thickness a bit some will fit my lower and drop free and some need the rear edges taken down a bit not much just a bit to drop free

tonelar
11-29-2011, 9:32 PM
If ordinary Stanags fit fine (and drop free), it's not your lower.

Do you have another Pmag to try?

hondamanr
11-29-2011, 9:32 PM
don't freeze the mag. check the bb tension.

mrvash
11-29-2011, 9:49 PM
Sounds like a mag catch issue, I would check to be sure you used the spring that came with the raddlock and not the spring that came with the LPK.

Yep, I'm sure I'm using the spring that came with the Raddlock, I even just doubled checked.

i've owned a spikes lower and used it with many pmags without any problems. i'd recommend checking your BB.

Just got back from checking the BB, everything seems fine with it.

try it without the bb installed and the upper off and see where it is rubbing or hitting and you will know if its the bb

I have noticed that pmags very in thickness a bit some will fit my lower and drop free and some need the rear edges taken down a bit not much just a bit to drop free

I also tried this test, I uninstalled the entire magazine release assembly and the PMAG was still a tight fit in the magwell.

If ordinary Stanags fit fine (and drop free), it's not your lower.

Do you have another Pmag to try?

Yes, the Stanags fit perfect, unfortunately I don't have another PMAG to try. The same PMAG though, fits my brother's Spike's lower alot better than mine and is almost drop free in his lower.


Also, I'm thinking I may have a lemon out of a bunch of Spike's lowers, because the finish also gets easily scratched :(..or is that normal?

RP1911
11-29-2011, 10:34 PM
if you have a Dremel, you can shave a bit off the mag depending on where the tight fit is.

Hoop
11-30-2011, 8:41 AM
Probably a combination of your lower having a slightly tight magwell and your pmag being a little big.

Munny$hot
11-30-2011, 9:27 AM
Pmags sometimes run big. Insert & remove the mag several times see where the rub marks are, then sand accordingly. Usually only the fronts require sanding. A small orbital palm sander works well and will keep everything even. Be sure to fit the mags cold and at warm temps since they do shrink and expand. If all this discourages you a excellent alternative is rebuild your pre-ban GI mags w/magpul followers.

boonyah
02-23-2012, 1:55 PM
Yeah i have the same issue with my spikes lower right now. It doesnt like 10/20 mags for some reason but the 10/30's fit fine. My friend got a spikes zombie lower and he has no issue with either. I found out from the place i bought it from (riflegear) that spikes switches manufacturers pretty often. I guess i got one with a tighter fit. Keep in mind i have a radlock but have no issues my promag 10/20's

MXRider
02-23-2012, 2:01 PM
If ordinary Stanags fit fine (and drop free), it's not your lower.

Do you have another Pmag to try?

False. The PMag is not made to the same spec as a STANAG magazine. Some lowers which are on the tighter end of the tolerance will have problems dropping a PMag.

If you removed the magazine release assembly and the mag won't easily slide out, your lower is the culprit.

RONIN.
02-23-2012, 3:10 PM
False. The PMag is not made to the same spec as a STANAG magazine. Some lowers which are on the tighter end of the tolerance will have problems dropping a PMag.

If you removed the magazine release assembly and the mag won't easily slide out, your lower is the culprit.

exactly.. so op.. take out the mag catch and radlock.. and see if the mag slides out..

if you insert the mag without the catch installed.. as if you were firing the rifle, the mag should drop out..

ronin.


if it does not, then your lower is on the tight side of the tolerances..

Sturnovik
02-23-2012, 4:11 PM
I just got my first and it has a spike lower, no issue with all 3 pmags I got. Hope its fixed budd.

nick
02-23-2012, 4:33 PM
Try it without the mag catch installed.

I've had a similar issue with 3 10/30 PMAGs (presumably from the same batch. At least, I got them in one purchase at the same store). The fitment of those would differ from lower to lower (tested with 5-6 different lowers), but even in the best case scenario they'd only drop free with a fair shake. At the same time, I don't have any issues with 10/20 PMAGs, a couple of other 10/30 PMAGs (bought at a different time), unaltered 30-rnd PMAGs from another batch (yes, in a featureless rifle), Troy polymer mags, or GI mags from different manufacturers. So it can easily be the mags.

boonyah
02-23-2012, 5:31 PM
Yeah i tried without the mag catch. Its definitely the mag well or the mag itself. I was thinking about modding the receiver but i think doing the mag itself is easier. Either that or just wait for some mega arms billets to become available.

MXRider
02-23-2012, 5:33 PM
Yeah i tried without the mag catch. Its definitely the mag well or the mag itself. I was thinking about modding the receiver but i think doing the mag itself is easier. Either that or just wait for some mega arms billets to become available.

If the lower is out of spec, call Spikes and see about getting it replaced. They (and others) have had out of spec lowers in the past.

boonyah
02-23-2012, 9:53 PM
i emailed them and they are blaming the pmags. im trying to work the mag over and over to see where there are some wear marks and try filing down the mag itself.

zvardan
02-24-2012, 10:54 AM
Some of the aero lowers have tighter tolerances in the magwell. I think spikes is using aero now (from what I've read).

I think rev 1 pmags had problems, rev 2 pmags seem to be ok.

Eddy's Shooting Sports
02-24-2012, 11:09 AM
Have you checked the alignment between your upper and lower?

Look in the magwell and see if there is a ridge or a smooth transition to the upper.

I have seen quite a few receivers out of spec that cause the mag to bind on the upper. (even from supposed "high end" brands)


Greg David
Eddy's Shooting Sports
400 Moffett Blvd., Suite F
Mountain View, CA 94043
(650)969-GUNS

boonyah
02-24-2012, 12:15 PM
Hmm,
I will try loading in a mag with the upper folded off. I never thought of that Eddy. Now that you mention it i think the upper may be slightly off. Im using an adams arms complete upper with the spikes lower. (sorry im very new to ar15's. This was my first build.) I still find it weird that the 20 round pmag body doesnt fit and the 30 round body does. Im already making plans to sell this spikes lower to a friend at a discounted price and i plan on getting a rifle gear aggressor lower instead.

The riflegear lower is made by mega and is pretty much the exact same as the mega forged lower minues the mega arms logo.


thanks for all the feedback guys!

cabinetguy
02-24-2012, 2:38 PM
have you tried another pmag? just to rule it out? I have a spikes lower, and pmags are tight, but not unjustifiably so

boonyah
02-24-2012, 3:14 PM
Yeah I have. Between me and my friend we have 12 of the 20 round body pmags.

motorwerks
02-26-2012, 8:09 PM
Just sand the Pmag a little. I had to do this with a couple of mine in my Tactical machining .308 Lower. I hated the idea but if you use some like 320 paper and jsut knock the top of the texture off, and then rub it down with some gun oil...... the only reason you can really tell is that your mags will now drop free.

Trickpony
02-26-2012, 8:23 PM
You'll have to modify the mag or use GI mags. I've seen this issue several times with some of the inexpensive lowers.

icenix
02-26-2012, 9:17 PM
Hmmmm. I have a 10/20 pmag and a Spikes lower and have had no problems. Hope you get it all figured out.

AJamesoo7
02-27-2012, 5:29 AM
Having the same issue with my LRB ARMS lower

ott1
02-27-2012, 10:16 AM
Check the date of manufacture on the left side of the mag just below the mag catch area. The dial arrow points to the month and on either side of the arrow is the year of manufacture. Magpul may have some batches that are slightly oversized.

Eddy's Shooting Sports
02-27-2012, 10:39 AM
Hmm,
I will try loading in a mag with the upper folded off.

What was the outcome of this?



Greg David
Eddy's Shooting Sports
400 Moffett Blvd., Suite F
Mountain View, CA 94043
(650)969-GUNS

boonyah
02-28-2012, 8:25 PM
thanks for all the help guys.

eddy: its the lower.

i decided to get a new lower. Got a mega arms forged =D Gonna pick it up next week!

Eddy's Shooting Sports
02-29-2012, 11:02 AM
thanks for all the help guys.

eddy: its the lower.

i decided to get a new lower. Got a mega arms forged =D Gonna pick it up next week!

As in "the lower is tight" or "the lower is out of alignment"? Just clarifying.

boonyah
02-29-2012, 12:49 PM
Sorry for not clarifying. The lower is tight. The guys at riflegear say that if lowers are made on the tighter side of the mil spec spectrum this happens with the 20 round pmags because those are intentionally made larger than your typical GI mag. They also said that 30 round pmags are the same dimmensions of a standard GI mag. (which is why those work)

gemini1
02-29-2012, 3:56 PM
I had the same issues on both 20s and 30s pmags, on a Superior Arms lower. I simply sanded down the back and sides and all is well now.