300 Blackout Magazines

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BJK
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Re: 300 Blackout Magazines

Post by BJK » Thu Oct 07, 2021 1:01 pm

Yeah, I was just putting out manufacturer info FWIW.

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dellet
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Re: 300 Blackout Magazines

Post by dellet » Fri Oct 08, 2021 9:37 am

BJK wrote:
Thu Oct 07, 2021 1:01 pm
Yeah, I was just putting out manufacturer info FWIW.
BJK wrote:
Wed Oct 06, 2021 11:26 pm
Short lesson, pardon me. Ignore if you wish.

If one thinks that one doesn't need 300BLK mags, then excellent. Let us know how you make out in the long term.
I don’t know who these three sentences were written by, but they are the three I was responding to.

They are a combination of both arrogance and ignorance. If they were from a manufacturer the intent was to sell a completely unnecessary product.

Any one who has spent any time on this forum knows I call out bullshit when I see it concerning the cartridge.

Dedicated magazines are a good idea. Way too many pictures posted of AR’s blown up from chambering Blackout cartridges in 223/556 chambers. I’ll throw this out there like I did on another forum.......

If the 300 Blackout cartridge chambers so easily in a 223/556 firearm, how come the only stories of blown up guns seem to be AR’s?

Are the AR shooters more the problem than the cartridge?
300 Blackout, not just for sub-sonics.

ReadyAimDuck
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Re: 300 Blackout Magazines

Post by ReadyAimDuck » Fri Oct 08, 2021 9:53 am

BJK wrote:
Wed Oct 06, 2021 11:26 pm
A 5.56 cartridge can weigh significantly less than a 300BLK round so the springs need to be stouter for 300BLK.
I can't really comment on how much the weight difference vs. spring rate or stoutness matters. All I can say is I've never had issues with 5.56 magazines. But this made me think. I wanted to check to see what the actual weight difference was. I'm only using the 110 grain bullets as an example because this is my go to supersonic load from hunting to defensive purposes, and I think its one of the most common bullet weights for those applications for others as well. Anyway, it occured to me that the weight difference may be slightly overstated when comparing 55 grain 5.56 to 110 grain 300 blackout. Not necessarily in the application of spring rate issues, but more in the realm of people doing the pros and cons of carrying around multiple fully loaded mags of the same caliber. I realized that people were doing the math wrong on that.

Its not true that 110 grain 300 blackout is 55 grains heavier per bullet. Because the 300 blackout cartridge has less brass and around half the powder. So I weighed the two and found that 110 grain blackout weighs about 33 grains more than 55 grain 5.56. In a 30 round magazine, that equates to 990 grains or 2.26 ounces. Obviously heavier bullets are going to weigh more. But does the extra 2.26 ounces when fully loaded change the way the springs behave enough to cause an issue? I would have to defer to someone with better mechanical knowledge. Either way, there are two things that I do know. The first is that I have not had any issues with 5.56 magazines in bullets that range from 110 grains to 220 grains. And that the weight difference between two of the most common loadings for each caliber is slightly over-stated. Especially when 5.56 bullets also commonly come in 70+ grain variety which makes for even less of a difference in weight to common 300 blackout bullets.

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dellet
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Re: 300 Blackout Magazines

Post by dellet » Fri Oct 08, 2021 10:05 am

Round numbers the Blackout case and powder charge weighs 20 grains less than a 223/556. Then the difference is bullet weight. Largest spread we’ll call 220 grains per round based on a 265 grain bullet and 10 grains of powder.

438 grains to an ounce. A 30 round magazine fully loaded is one pound heavier. 300 Blackout vs 55 grain 223.

To many videos of full auto subs using standard magazines to think it’s really a problem. The springs will need to be replaced more often.

I will add that there were problems with the 60 round Surefire magazines and 100 round drums.
300 Blackout, not just for sub-sonics.

BJK
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Re: 300 Blackout Magazines

Post by BJK » Sat Oct 09, 2021 3:34 pm

The 300BLK specific mags also have ribs that are different near the bullet nose. Supposedly a standard mag can interfere with 300BLKs. They look pretty much the same but the difference in construction is there.

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