Flash can muzzle slightly short of handguard

Astocks2622 · September 5, 2017, 06:43 PM

I'm putting together my first AR pistol, and have to into a slight problem. I have a KAK 8.5" 300BLK barrel, Micro Flash can, and 10" ALG handguard. The handguard hasn't arrived yet, but when I threw the flash can on the barrel, I'm only measuring about 9" from the barrel shoulder to the muzzle of the can. If I've done my math right, including the .45" it upper barrel threads with are also covered by the handguard, this will put the handguard forend about 3/8" forward of the flash can muzzle.
1st, did I forget anything in my dimensions that means the can will end up flush out beyond the guard?
2nd, assuming the can muzzle is slightly (3/8") short of the handguard, do I actually have an issue? The flash can is designed as a forcing cone, directing blast and gasses forward, not up or sideways. I've seen pictures of guys blowing their handguards apart with a compensator under it, but will a flash can do the same thing over time?
Worse comes to worst, I can buy the standard length Slimline flash can and have a full inch beyond the guard.
Thanks for your help!

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**44 AMP** · September 5, 2017, 10:59 PM

I freely admit I don't know the specifics of the parts you are talking about, but, consider this, powder gas erodes STEEL. It eats steel barrels, over time.

Anything projecting beyond the muzzle will eventually be damaged by powder gas, and if its not steel to begin with, the process could happen fairly soon.

Astocks2622 · September 6, 2017, 12:39 AM

I know. That's what's got me worried! I wouldn't even think about it if it were a normal muzzle device. Watching videos of the KAK flash cans, it looks like almost all of the gasses are forced into a cone beginning several inches from the muzzle. Anyone have experience with this issue specifically?

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stagpanther · September 6, 2017, 06:50 AM

Carbide tipped radial saw blade from home depot and 10 seconds later your handguard problem solved.

zukiphile · September 6, 2017, 08:21 AM

The issue I foresee isn't the safety of an aluminium handguard (another of which can be purchased), but the safety of peoples' hands. That it is a "handguard" will suggest to people that it is reasonable to place one's hands anywhere on the guard.

You would not like to hand this to someone only to have him place his hand in a manner that would leave him injured.

Fishbed77 · September 6, 2017, 08:38 AM

Quote:

Carbide tipped radial saw blade from home depot and 10 seconds later your handguard problem solved.

Or just order a longer muzzle device.

Mobuck · September 7, 2017, 06:22 AM

Don't let your digits overhang the handguard!!!!!!!!!!

stagpanther · September 7, 2017, 06:23 AM

Quote:

Don't let your digits overhang the handguard!!!!!!!!!!

Unless you want to convert one to a front sight.

Astocks2622 · September 7, 2017, 10:49 AM

Quote:

Originally Posted by stagpanther

Unless you want to convert one to a front sight.

Or a rear peep sight, if you use a small enough cartridge...
I ordered a longer flash can. We'll see how close the shorty comes to the end if the guard when it gets here.

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Chainsaw. · September 8, 2017, 01:10 PM

Ive personally blown plywood apart with a brake, take a 4" chuck out of one layer at a time. An aluminum handguard would fair better but not by much. Get the longer muzzle device once you get the handguard in...hand.

Btw, I did this when building my AR9. Oops.

mellow_c · September 8, 2017, 02:55 PM

I would say to go for the longer slim flash can, if you need the slim one that is. Otherwise you could just get the standard kak flash can.

If you are correct and the micro ends up being a bit short and ending slightly inside the hand guard, not only will you have "concerns" regarding safety and possible damage to the hand guard, but it will just look funny too. If you spend the $20-$30 to buy the longer one you wont have to worry about anything and it will look better.

If you decide to do that, let me know, I might buy your micro from you if you want to get rid of it cheap

Astocks2622 · September 9, 2017, 12:28 PM

Yeah, it's definitely too short. The longer can and buis should be here Monday.

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stagpanther · September 9, 2017, 05:26 PM

ditch the rail for a proper length one.

Astocks2622 · September 9, 2017, 07:14 PM

Quote:

Originally Posted by stagpanther

ditch the rail for a proper length one.

Nope. This is the shortest rail if this design ALG makes, and is the style I want. I'll just throw on the flash can that's 3.25" instead of the 1.75" one. That will put the muzzle 1" forward of the rail.

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stagpanther · September 9, 2017, 10:28 PM

Quote:

Nope. This is the shortest rail if this design ALG makes, and is the style I want. I'll just throw on the flash can that's 3.25" instead of the 1.75" one. That will put the muzzle 1" forward of the rail.

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Proper length rail seems to me to be a better alternative than "compensating length" compensator or suppressor--but I have no experience with such arrangements. I have also never seen a weapon configured that way, either. Good luck.

Rob228 · September 10, 2017, 12:12 AM

You could save yourself the $ from the new muzzle brake and just buy a suppressor, of all the reasons to buy one, this seems pretty high up there.

Astocks2622 · September 10, 2017, 10:11 AM

Hmm, I don't think the wife will buy that one...
"Honey, I saved $35 by buying a $600 suppressor, (plus $200 for the tax stamp)"

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Chainsaw. · September 11, 2017, 01:55 PM

Ive got a kak blast diverter laying around Ill sell ya. Pretty sure its the long regular sized one, ie not slim.
1/2 36 iirc

Astocks2622 · September 12, 2017, 08:30 PM

All set with the new flash can. It looks better and no worries about blowing my rail apart. I also put on an afg, mostly to prevent unintentional perforation of my digits. I'll throw pics up when I get home. I did have some failures to feed with the new pistol, but I'll start a separate thread on troubleshooting that.

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Astocks2622 · September 12, 2017, 08:58 PM

Here are the pics.

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TheDevilThatYouKnow · September 12, 2017, 09:19 PM

Looking good, Astocks2622

https://www.youtube.com/watch?v=XtKydtoLucc

Ibmikey · September 14, 2017, 12:22 AM

My 8 1/2" barrel 300 Blackout pistol with a full length hand guard and Faxon " loud mouth" brake is quite enjoyable to shoot and I have never come close to putting my hand too far forward on the guard. The top of the rail is raised and has a sight on it the bottom has a rail section for the adding of accessories, both let the hand know how far forward it is.

armoredman · September 14, 2017, 02:44 AM

What does a "flash can" do, anyway?

Astocks2622 · September 14, 2017, 09:40 AM

Quote:

Originally Posted by armoredman

What does a "flash can" do, anyway?

Mostly just directs the sound and flash forward instead of up or back like a compensator or flash hider.

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stagpanther · September 14, 2017, 10:59 AM

Hmmm--kinda counter-intuitive for a short-barreled AR no?

September 5, 2017, 06:43 PM	#1
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	Flash can muzzle slightly short of handguard I'm putting together my first AR pistol, and have to into a slight problem. I have a KAK 8.5" 300BLK barrel, Micro Flash can, and 10" ALG handguard. The handguard hasn't arrived yet, but when I threw the flash can on the barrel, I'm only measuring about 9" from the barrel shoulder to the muzzle of the can. If I've done my math right, including the .45" it upper barrel threads with are also covered by the handguard, this will put the handguard forend about 3/8" forward of the flash can muzzle. 1st, did I forget anything in my dimensions that means the can will end up flush out beyond the guard? 2nd, assuming the can muzzle is slightly (3/8") short of the handguard, do I actually have an issue? The flash can is designed as a forcing cone, directing blast and gasses forward, not up or sideways. I've seen pictures of guys blowing their handguards apart with a compensator under it, but will a flash can do the same thing over time? Worse comes to worst, I can buy the standard length Slimline flash can and have a full inch beyond the guard. Thanks for your help! Sent from my MotoG3 using Tapatalk

September 5, 2017, 10:59 PM	#2
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,846	I freely admit I don't know the specifics of the parts you are talking about, but, consider this, powder gas erodes STEEL. It eats steel barrels, over time. Anything projecting beyond the muzzle will eventually be damaged by powder gas, and if its not steel to begin with, the process could happen fairly soon. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

September 6, 2017, 06:50 AM	#4
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,789	Carbide tipped radial saw blade from home depot and 10 seconds later your handguard problem solved. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

September 6, 2017, 08:21 AM	#5
zukiphile Senior Member Join Date: December 13, 2005 Posts: 4,457	The issue I foresee isn't the safety of an aluminium handguard (another of which can be purchased), but the safety of peoples' hands. That it is a "handguard" will suggest to people that it is reasonable to place one's hands anywhere on the guard. You would not like to hand this to someone only to have him place his hand in a manner that would leave him injured. __________________ http://www.npboards.com/index.php

September 8, 2017, 01:10 PM	#10
Chainsaw. Senior Member Join Date: September 12, 2015 Location: Issaquah WA. Its a dry rain. Posts: 1,774	Ive personally blown plywood apart with a brake, take a 4" chuck out of one layer at a time. An aluminum handguard would fair better but not by much. Get the longer muzzle device once you get the handguard in...hand. Btw, I did this when building my AR9. Oops. __________________ Just shoot the damn thing.

September 6, 2017, 12:39 AM	#3
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	I know. That's what's got me worried! I wouldn't even think about it if it were a normal muzzle device. Watching videos of the KAK flash cans, it looks like almost all of the gasses are forced into a cone beginning several inches from the muzzle. Anyone have experience with this issue specifically? Sent from my MotoG3 using Tapatalk

September 7, 2017, 06:22 AM	#7
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	Don't let your digits overhang the handguard!!!!!!!!!!

September 8, 2017, 02:55 PM	#11
mellow_c Senior Member Join Date: January 7, 2008 Location: Colorado Posts: 1,862	I would say to go for the longer slim flash can, if you need the slim one that is. Otherwise you could just get the standard kak flash can. If you are correct and the micro ends up being a bit short and ending slightly inside the hand guard, not only will you have "concerns" regarding safety and possible damage to the hand guard, but it will just look funny too. If you spend the $20-$30 to buy the longer one you wont have to worry about anything and it will look better. If you decide to do that, let me know, I might buy your micro from you if you want to get rid of it cheap

September 9, 2017, 12:28 PM	#12
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	Yeah, it's definitely too short. The longer can and buis should be here Monday. Sent from my MotoG3 using Tapatalk

September 9, 2017, 05:26 PM	#13
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,789	ditch the rail for a proper length one. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

September 10, 2017, 12:12 AM	#16
Rob228 Senior Member Join Date: May 29, 2010 Location: Hampstead NC Posts: 1,450	You could save yourself the $ from the new muzzle brake and just buy a suppressor, of all the reasons to buy one, this seems pretty high up there.

September 10, 2017, 10:11 AM	#17
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	Hmm, I don't think the wife will buy that one... "Honey, I saved $35 by buying a $600 suppressor, (plus $200 for the tax stamp)" Sent from my MotoG3 using Tapatalk

September 11, 2017, 01:55 PM	#18
Chainsaw. Senior Member Join Date: September 12, 2015 Location: Issaquah WA. Its a dry rain. Posts: 1,774	Ive got a kak blast diverter laying around Ill sell ya. Pretty sure its the long regular sized one, ie not slim. 1/2 36 iirc __________________ Just shoot the damn thing.

September 12, 2017, 08:30 PM	#19
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	All set with the new flash can. It looks better and no worries about blowing my rail apart. I also put on an afg, mostly to prevent unintentional perforation of my digits. I'll throw pics up when I get home. I did have some failures to feed with the new pistol, but I'll start a separate thread on troubleshooting that. Sent from my MotoG3 using Tapatalk

September 12, 2017, 08:58 PM	#20
Astocks2622 Member Join Date: February 1, 2014 Posts: 97	Here are the pics. Sent from my MotoG3 using Tapatalk

September 12, 2017, 09:19 PM	#21
TheDevilThatYouKnow Member Join Date: November 22, 2015 Posts: 89	Looking good, Astocks2622 https://www.youtube.com/watch?v=XtKydtoLucc

September 14, 2017, 12:22 AM	#22
Ibmikey Senior Member Join Date: June 1, 2013 Location: Now relocated to Texas Posts: 2,943	My 8 1/2" barrel 300 Blackout pistol with a full length hand guard and Faxon " loud mouth" brake is quite enjoyable to shoot and I have never come close to putting my hand too far forward on the guard. The top of the rail is raised and has a sight on it the bottom has a rail section for the adding of accessories, both let the hand know how far forward it is.

September 14, 2017, 02:44 AM	#23
armoredman Senior Member Join Date: May 22, 2007 Location: Arizona Posts: 5,299	What does a "flash can" do, anyway?

September 14, 2017, 10:59 AM	#25
stagpanther Senior Member Join Date: March 2, 2014 Posts: 11,789	Hmmm--kinda counter-intuitive for a short-barreled AR no? __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*