7.62 can on a 5.56mm gun.....

BufordTJustice · #1 09-21-11, 04:11

Okay, So I heard a fellow deputy (who regularly endorses dpms as a 'premium quality AR15') spout something that made my bullshit detector go off. Problem is, I have ZERO experience with suppressors, other than shooting a few handguns and an AR with one....so I wasn't able to prove he was full of shit on the spot. So here goes....

He said that not only can you use a 7.62 sized suppressor on a 5.56mm gun (not debating this, assuming the mounts match), but that it is BETTER to use a 7.62 can on a 5.56 AR because the 7.62 can will be QUIETER. I then made the mistake of immediately calling bullshit on this (pure reflex, I tell ya). Which became a problem, because all of this fucker's robot-buddies started their, "Yeah, what he said!" chorus and I told them to all go to hell....and then briefing was over and we had to go ten-8.

I made no bets, but I'm certain this topic will come up again tomorrow or the next day. I'm calling on you: Markm, IGunz, or MagicSalad. I need you guys to cut through the bullshit and give me the skinny on this.

Thank you in advance.

CoryCop25 · #2 09-21-11, 04:19

I can answer the first part of your question. YES, you can shoot 5.56 out of a 7.62 can. Is it better? Not sure about that one... the pros will have to chime in on that one.

TehLlama · #3 09-21-11, 05:20

It is certainly possible to get reduced dBkPa (pressure - sound equivalent) readings off a 7.62 can against a 5.56 can, but ONLY because the former is probably a can with significantly more volume. Usually an overbore can gives up about twofold (2-3dB) sound reduction, but since many 22 cal centerfire rifle cans are on the light-small size when compared to their 7.62 bretheren, it's possible to have a large 30 cal can 'outperform' it in pure sound reduction.

You still have a larger, heavier, more expensive can, one which would be more efficient with a 22 caliber bore, but I doubt these guys were savvy enough on this.
If it's a range-only item, and pure sound reduction is the goal, then a big, fat, long enormous can in any caliber isn't a bad idea, and with the competitive price point of some (YHM comes to mind) it's actually not a crazy idea... but I'd absolutely rather have a smaller, lighter, more efficient 22Cal can from OPS/AAC/SF than something huge for any sort of fighting rifle.

sinister · #4 09-21-11, 11:19

(Older) Common practice for many units to use a 7.62 suppressor on a 5.56mm weapon, especially in the days pre-SOPMOD.

A 7.62mm cartridge may have twice the propellant charge of a 5.56. The suppressor for a 7.62 will delay the escape of high pressure gas and have (nominally) twice the volume of a 5.56mm suppressor. More gas will leak from around the bullet as it clears the muzzle crown but is really inconsequential in the scheme of things as the gas goes into disruption in the blast baffle and subsequent expansion chamber and baffles.

JasonM · #5 09-21-11, 11:49

Your fellow deputy is completely right in general terms-

A 7.62 can will work just fine on a 5.56 gun. In simple terms, the lost efficiency from the larger bore is made up for by the larger volume of the 30 cal can.

Again, in general terms, 762 can vs 556 can on a 5.56 host:

Pros-
- less backpressure and therefore potentially quieter to the shooter
- Larger bore gives you more 'protection' from baffle strikes

Cons-
- Larger
- heavier

Ironman8 · #6 09-21-11, 12:09

Jason since we have you here, I was wondering...and hopefully this isn't too off topic...but can the AAC 6.8 SPR/M4 be used on a .270 bolt gun?

Todd.K · #7 09-21-11, 12:12

Quieter, no. Some 7.62 silencers may be slightly quieter than some 5.56 silencers.

In general they are almost as quiet, but if you made them both the same size the 7.62 silencer should be noticeably louder.

JasonM · #8 09-21-11, 14:15

Quote:

Originally Posted by Ironman8

Jason since we have you here, I was wondering...and hopefully this isn't too off topic...but can the AAC 6.8 SPR/M4 be used on a .270 bolt gun?

hmm, I would check with Mike Mers (mers@advanced-armament.com) or John Holister (john@advanced-armament.com).

I know the 762 cans are OK with it, but I'd confirm with one of those guys.

ccosby · #9 09-21-11, 18:39

As others have said yes a 7.62 suppressor can be mounted on a 5.56 rifle either via a thread adapter or via a suppressor mount.

Generally speaking the 7.62 suppressor will be a little bit louder although not by much. Generally speaking the big trade off is size and weight. If you have other rifles that can use the 7.62 suppressor(or other 30 cal suppressors) then buying a single suppressor for multiple rifles may make sense. If you only have a 5.56 rifle I'd stick with a 5.56 suppressor.

english kanigit · #10 09-21-11, 20:13

Funny this subject comes up. I've been really wondering about have a SF 762MINI-T (when they come out

) for use on an AK, SCAR and AR15. I believe it will fit the SF 556 mounts. Seems like an excellent way to be 'efficient' with limited funds.

Ek

scottryan · #11 09-21-11, 21:05

The deputy is a moron.

A 5.56 silencer and a 7.62 silencer made the same size, the 5.56 will be quieter.

ccosby · #12 09-21-11, 21:57

Quote:

Originally Posted by scottryan

The deputy is a moron.

A 5.56 silencer and a 7.62 silencer made the same size, the 5.56 will be quieter.

Yea but I don't think that is what he was saying. Generally the 30 cal suppressors are going to be bigger.

scottryan · #13 09-22-11, 12:19

Quote:

Originally Posted by ccosby

Yea but I don't think that is what he was saying. Generally the 30 cal suppressors are going to be bigger.

Yeah they are, but that deputy is a moron and is misleading. He makes it should like a 5.56 silencer shouldn't even exist.

fixit69 · #14 09-22-11, 20:09

Well this is my second attempt, let see if this goes through...

The can will work.

No, it is not quieter.

I find it more useful, larger calibers, etc...

At the rate my post is posting, ten people probably have said the same thing.

JadeRaven · #15 09-22-11, 23:07

Sure same size, the 5.56 can will be quieter. However, the fact is most 7.62 cans are bigger and could very well be quieter compared to your average 5.56 can.

But yeah blanket statement wise he's prolly full of it

Personally - I put my money on a 762SDN-6 for my 5.56 . It's an inch longer and two ounces heavier, but it does great with 5.56 and allows me to dream of moving into 300blk and even .308.

BufordTJustice · #16 09-26-11, 00:16

Thank you to all who responded. I got exactly the info I was looking for.

A 7.62 can can be made to work on a smaller caliber weapon, but it is not optimal. He and his buddies did bring it up again yesterday...and they were made to look like asshats...even made my captain laugh.

Thanks again for chiming in with your experience and knowledge.