Which AR magazine works best for Whisper??

[tpfdchn]

This question has probably been asked and answered more than once, but since I don't frequent the boards often, here goes: All my AR magazines have internal ribs that guide the .22 cal bullets into the feed ramps. The larger .30 cal bullets jam on these and won't feed reliably.

There's got to be a better solution than skiving these ribs off from P-mags with a wood chisel.

Help out a newbie here and let me know what the best solution is for this. There's got to be AR mags out there that are suitable for .300 Whisper.

Thanx,

[HotLead]

It depends on the bullet seat depth and the ogive of the bullet.
I have been shooting 180 and 190 grain Sierra Match Kings seated to 2.230", and USGI mags work flawlessly; Pmags will not work with this load.
If you push the bullet deeper in to casing, the magazine rib should not push the bullet inward.

[Retooferab]

I am using 20 P mags. I seat my bullets from 2.09 to 2.19 oal.

[buffetdestroyer]

With different bullets having different profiles, I have found that some seating depths are reliable and some won't work out of anything. The seating depth of my 220 Grain load is 2.09", while my 175 Grain load is closer to 2.15".

I would recommend a no tilt follower in any magazine that you use. The 20 round PMags don't work as well as the 30 round PMags for my pet loads (they will sometimes tilt down enough that the BCG will miss the butt of the round and not chamber). You can always load up a few dummy rounds to hand cycle if you are experimenting, but the 30 round PMags work well in mine and I have gotten rid of most of my USGI mags because I like that the PMags' retaining lips have less friction and don't scar up the brass like the old steel ones did. And PMags are relatively inexpensive, durable and easy to color code for caliber separation. FDE = .223/5.56 and Black = .300 WTF

[srm109]

I have had really good luck with my C-Products magazines. I have 2 10-round magazines that I use to hunt. I also have 3 30-round magazines that are "military" issue that work perfectly (the ones that come in the green plastic bags).

One of my C-products magazines was rubbing against the bottom of the bolt carrier and caused a little shiny spot on the top corner of the magazine. It still worked perfectly, but I took a small file and relieved the top of the hole where the magazine catch goes just to give it a little more room.

[gds]

I have had success with 20 and 30 rnd p mags, and 30 rnd GI mags. The older 20 rnd GI mags will not feed reliably for me. I also bought a 20 rnd Tango down mag that I cannot get to feed reliably with .300 whatever or .223

My Loadings and lengths

125 Sierra SPFB 2.010
130 Hornady SPFB 2.010
200 cast 1.990
155 Cast 1.971
150 FMJ 2.065
178 Hornandy A-MAX 2.195