The Down Range Forum

Member Section => Building America's Rifle => Topic started by: tombogan03884 on November 27, 2021, 09:42:13 AM

Title: 300 BLK mags
Post by: tombogan03884 on November 27, 2021, 09:42:13 AM
I know Les answered this for me before, but darned if I can find it.   ;D

Bought 30 rd AR mags.  Curve is wrong for the 300 cartridge , so they're basically cool looking 5 rounders.        :(

Should I have just bought 20 rd mags ?
Or does some one make 300 specific mags ?

Thanx   ;D
Title: Re: 300 BLK mags
Post by: PegLeg45 on November 27, 2021, 05:43:33 PM
I've been considering building out a .300 on a spare receiver and wonder this as well.
When the .300 Blk first came on the scene, all the "experts" said one of the advantages was mag compatibility.
Title: Re: 300 BLK mags
Post by: tombogan03884 on November 27, 2021, 09:16:46 PM
The taper is different so they don't stack the same.   >:(
As well as wider so mag capacity is a bit lower as well.
Title: Re: 300 BLK mags
Post by: alfsauve on November 28, 2021, 07:44:34 AM
See if I can get Kevin to respond he loves his .300.

Slight different animal, but I use straight, metal 20 rounders for my .458.  Did replace the follower with a single stack one.  Not really necessary but heads off any feeding problem with the last round.   
Title: Re: 300 BLK mags
Post by: tombogan03884 on November 28, 2021, 08:23:24 AM
See if I can get Kevin to respond he loves his .300.

Slight different animal, but I use straight, metal 20 rounders for my .458.  Did replace the follower with a single stack one.  Not really necessary but heads off any feeding problem with the last round.

That's what I plan on pending other suggestions.
One issue I have is I want to keep 300, and 5.56 unmistakably separate.
Right now I have metal for 5.56, and polymer for 300.
Title: Re: 300 BLK mags
Post by: alfsauve on November 28, 2021, 03:40:52 PM
I use Ammo Bands on any that aren't 5.56.  Of course all I got is .458 and .308 right now.

I have one metal 10 rounder also for .458.  Only holds 5.  It doesn't get in the way as much shooting from the bench.  Also had the idea that if I went to hunt in a state with magazine restriction it would be what I'd use.
Title: Re: 300 BLK mags
Post by: Pathfinder on December 01, 2021, 10:41:04 AM
Magpul makes .300BLK mags, I have 10 or so, also banded. I even have a special band for the sub-sonic 300s.

X-Products allegedly makes a drum mag for the 300, but I have yet to find it on their website.
Title: Re: 300 BLK mags
Post by: les snyder on December 11, 2021, 05:40:05 PM
I just had a talk with my friend from SOCOM... and asked him about the 300BLK magazines....as used in the SiG MCX as adopted by SOCOM, they use standard M4/16 magazines in the MCX.... 220grain Barnes bullet with magnum pistol powder.... switch was from previously used HK MP5SD that had holes drilled in the barrel proper in addition to baffled suppressor so NATO standard 9mm would be sub sonic... a 147 at less than 1000fps is basically a .38spl, and was over matched in one of the Euro terrorist confrontations against 7.62/5.45x 39 with poor outcome for the good guys
Title: Re: 300 BLK mags
Post by: tombogan03884 on December 12, 2021, 08:33:58 AM
I just had a talk with my friend from SOCOM... and asked him about the 300BLK magazines....as used in the SiG MCX as adopted by SOCOM, they use standard M4/16 magazines in the MCX.... 220grain Barnes bullet with magnum pistol powder.... switch was from previously used HK MP5SD that had holes drilled in the barrel proper in addition to baffled suppressor so NATO standard 9mm would be sub sonic... a 147 at less than 1000fps is basically a .38spl, and was over matched in one of the Euro terrorist confrontations against 7.62/5.45x 39 with poor outcome for the good guys

That's actually a fairly common practice in dedicated suppressed guns.
Forgotten Weapons has a video of a newer model/ prototype that let's you open or close the holes for sonic or sub- sonic ammo.
I don't recall the maker or I would link the vid.
Title: Re: 300 BLK mags
Post by: Big Frank on December 04, 2022, 02:39:15 AM
I use Ammo Bands on any that aren't 5.56.  Of course all I got is .458 and .308 right now.

I have one metal 10 rounder also for .458.  Only holds 5.  It doesn't get in the way as much shooting from the bench.  Also had the idea that if I went to hunt in a state with magazine restriction it would be what I'd use.

The ammo bands are a good idea. Even though I don't own either one, I like the .458 SOCOM better than the .458 Bushmaster. The fact that the cartridge takes up the full width of the magazine, and the feed lips don't need to be modified is part of the reason. If I deer hunted in the shotgun zone here I would have to use straightwall cartridges, dut I don't plan on deer hunting anymore. If I buy either one it will likely come down to a .458, it being cheaper and the ammo more available.
Title: Re: 300 BLK mags
Post by: Big Frank on December 04, 2022, 02:51:50 AM
That's actually a fairly common practice in dedicated suppressed guns.
Forgotten Weapons has a video of a newer model/ prototype that let's you open or close the holes for sonic or sub- sonic ammo.
I don't recall the maker or I would link the vid.

I never heard of one you can close the holes in the barrel on. I imagine it's a sleeve with holes over the barrel that only needs to turn a little bit like some compensators/brakes. Or possibly it moves in and out a bit. That would be really easy to do with a lever on the receiver. For a long time I didn't know the MP5SD sub-gun had a perforated barrel making sub-sonic ammo unnecessary. There are so many holes in the barrel it bleeds off the velocity of standard ammo to sub-sonic before it gets to the muzzle. That's different from most sub-guns, although holes in the barrel are common practice as you said.