300blk subsonic (carbine gas)

[Moorvogi]

Search is slow (virus scan maybe??) atm but I'm guessing someone has had this problem/question already.

ANYWAY... does anyone have a load for a CARBINE length gas block 300blk that is subsonic AND cycles your bolt? I'll do my own research and at my own risk but was looking for some potential savings. I'm told by some it "can't be done w/ carbine" and others say it CAN.

Some say you need an adjustable gas block to tune it but if its full open (max gas) and it still doesn't cycle.. making LESS gas thru.. seems like it would be counter productive.

My plan atm is to pick a bullet, pick a powder and start w/ couple tenths of a grain above minimum charge. Work down and stop when it stops cycling or i meet my goal (subsonic AND cycle bolt).

Worst case scenario, i redo all the testing on my pistol. I'm a BIG FRAME guy at 6' 4" 250lbs.. i find ar pistols are not comfortable to shoot.

If the pistol length works where the carbine doesn't at all.. i'll consider SBR the pistol length or getting a carbine length barrel w/ pistol length gas port.

Annnyway.. looking to save a buck from someone who has first hand experience. not a friend of a friend who heard from a guy that owned a gun that loaned it to someone and they said ........... you get the idea.

 

[mtlcafan79]

16" carbine gas barrels will cycle with the correct powders and a can attached. You may not get last round BHO every time though. I would start with 220gr pills and A1680 if you've got it. 300blktalk has a lot of this documented pretty well.

 

[Moorvogi]

16" carbine gas barrels will cycle with the correct powders and a can attached. You may not get last round BHO every time though. I would start with 220gr pills and A1680 if you've got it. 300blktalk has a lot of this documented pretty well.

rgr that. will try site again. i think there's something fishy w/ my internet hamsters at the moment. thanks!

 

[outrider58]

I don't own a 300AAC with carbine gas. I don't think I know anyone(off hand) who does. I don't think it would be impossible, yet I have never tried.


I do know that 16" pistol length gas cycles them with or without adjustable gas.

As mtlcafan79 said A1680 is one of the best subsonic powders for working up loads. I would recommend trying different bullet weights ranging from 190gr up to 225grs. That may make the difference.

 

[John from MD]

I own a 300 carbine gas ( I built it when they were first coming out). It took a lot of work to get reliable loads that would work with 150gn lead bullets at supersonic speeds. I can't imagine shooting the 208's etc at subspeeds unless you have a can and you still may have to open up your gas port.

 

[outrider58]

I own a 300 carbine gas ( I built it when they were first coming out). It took a lot of work to get reliable loads that would work with 150gn lead bullets at supersonic speeds. I can't imagine shooting the 208's etc at subspeeds unless you have a can and you still may have to open up your gas port.

I have defended shooting subs in 300 blk in the past(light loads for youths etc), but in the OP's case, I don't see any reason to shoot subs without a can, unless I missed something...

 

[John from MD]

I was just saying the only way it MAY work, is with a can. If I was building it all over again, I would use pistol gas. Now that I have mine running well, I have no reason to change. Amazingly it also shoots factory Remington 120gn rounds well also without any over pressure signs or beating up the brass.

 

[DaemonAssassin]

Search is slow (virus scan maybe??) atm but I'm guessing someone has had this problem/question already.

ANYWAY... does anyone have a load for a CARBINE length gas block 300blk that is subsonic AND cycles your bolt? I'll do my own research and at my own risk but was looking for some potential savings. I'm told by some it "can't be done w/ carbine" and others say it CAN.

Some say you need an adjustable gas block to tune it but if its full open (max gas) and it still doesn't cycle.. making LESS gas thru.. seems like it would be counter productive.

My plan atm is to pick a bullet, pick a powder and start w/ couple tenths of a grain above minimum charge. Work down and stop when it stops cycling or i meet my goal (subsonic AND cycle bolt).

Worst case scenario, i redo all the testing on my pistol. I'm a BIG FRAME guy at 6' 4" 250lbs.. i find ar pistols are not comfortable to shoot.

If the pistol length works where the carbine doesn't at all.. i'll consider SBR the pistol length or getting a carbine length barrel w/ pistol length gas port.

Annnyway.. looking to save a buck from someone who has first hand experience. not a friend of a friend who heard from a guy that owned a gun that loaned it to someone and they said ........... you get the idea.

I have a 16" barrel with pistol gas. It will cycle anything I feed it, with no issues. It does not have an adjustable block either. Relatively good accuracy with it too. See for yourself in the link below.

https://www.mdshooters.com/showpost.php?p=4896240&postcount=19

Bear in mind that when you are loading for subs, there is no listed minimum charge, only the maximum charge.

https://sierrabulletsblog.com/2017/12/21/sierra-bullets-300-aac-blackout-load-data/

Hope this helps.

 

[clandestine]

Yes you can get a .300 to cycle subs with carbine gas. It usually takes work/tuning to get the weapon setup for it.

Carbine gas .300 is terrible.

 

[smokey]

What buffer?

 

[John from MD]

For mine, I use an H3.

 

[Moorvogi]

I own a 300 carbine gas ( I built it when they were first coming out). It took a lot of work to get reliable loads that would work with 150gn lead bullets at supersonic speeds. I can't imagine shooting the 208's etc at subspeeds unless you have a can and you still may have to open up your gas port.

A can will be attached (after atf jail) and it’s a non adjustable gas block so... “full of gas” instead of blessing it off.

I can cycle 110-168 supers no problems in mine without a can. It gets a little Squirrley beyond that so I stuck with 168 gr AMaX while they were making them still.


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[Moorvogi]

I have defended shooting subs in 300 blk in the past(light loads for youths etc), but in the OP's case, I don't see any reason to shoot subs without a can, unless I missed something...

This is going to be with a can but.. a viable option would be for hunting.... if it was your only gun maybe..? Haha. Not sure. I’ve avoided the subsonic hunting for a while because MD hunting requirements. Then I realized that the energy requirements are different (non existant) for “pistols”.

You needs 1,200+ foot ponds at the muzzle to hunt deer with a rifle. Pistols don’t have that requirement. Dumb but... you can take a 357 magnum rifle/carbine and it’s illegal... same ammo and shorter barrel (pistol) for lower energy and BAM... its legal again.

Therefore... hunting with a subsonic load is fine... if it’s a “pistol”. There are a couple other differences but that one is hilarious. I pointed it out to DNR when they allowed air guns to be used... no change yet..


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[Moorvogi]

I have a 16" barrel with pistol gas. It will cycle anything I feed it, with no issues. It does not have an adjustable block either. Relatively good accuracy with it too. See for yourself in the link below.

https://www.mdshooters.com/showpost.php?p=4896240&postcount=19

Bear in mind that when you are loading for subs, there is no listed minimum charge, only the maximum charge.

https://sierrabulletsblog.com/2017/12/21/sierra-bullets-300-aac-blackout-load-data/

Hope this helps.

Thanks m8! I have a carbine length and a pistol... just uncomfortable to shoot the pea shooter pistol with my large stature.


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[Moorvogi]

Yes you can get a .300 to cycle subs with carbine gas. It usually takes work/tuning to get the weapon setup for it.

Carbine gas .300 is terrible for .300

Less than ideal in some of your situations perhaps but I suppose it depends on POU. How you use it will dictate that stance. If you only shoot supers... it’s better in my opinion. Less gas back in your face and still functions the gun.

Perhaps what you ment was “carbine gas .300 is terrible for .300 subs”. ..?

Hind site 20/20.... I have had my carbine for 6 years and a few thousand rounds now and only considering changing to pistol length because my can easily FINALLY approved.


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[outrider58]

This is going to be with a can but.. a viable option would be for hunting.... if it was your only gun maybe..? Haha. Not sure. I’ve avoided the subsonic hunting for a while because MD hunting requirements. Then I realized that the energy requirements are different (non existant) for “pistols”.

You needs 1,200+ foot ponds at the muzzle to hunt deer with a rifle. Pistols don’t have that requirement. Dumb but... you can take a 357 magnum rifle/carbine and it’s illegal... same ammo and shorter barrel (pistol) for lower energy and BAM... its legal again.

Therefore... hunting with a subsonic load is fine... if it’s a “pistol”. There are a couple other differences but that one is hilarious. I pointed it out to DNR when they allowed air guns to be used... no change yet..


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I believe there is a minimum energy for pistols in Md of 750 ft/lbs.

I poopoo that because we kill deer all the time with pointy sticks.

 

[clandestine]

Less than ideal in some of your situations perhaps but I suppose it depends on POU. How you use it will dictate that stance. If you only shoot supers... it’s better in my opinion. Less gas back in your face and still functions the gun.

Perhaps what you ment was “carbine gas .300 is terrible for .300 subs”. ..?

Hind site 20/20.... I have had my carbine for 6 years and a few thousand rounds now and only considering changing to pistol length because my can easily FINALLY approved.


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No, I meant exactly what I said.

I was completely lost till you set me straight.

 

[Moorvogi]

No, I meant exactly what I said.

I was completely lost till you set me straight.

Oh. Okay well... I guess you have a right to say what you want. Laph out loud.


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[DaemonAssassin]

Oh. Okay well... I guess you have a right to say what you want. Laph out loud.


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You really want to get on his bad side, that's cool. But I'd recommend you choose your path wisely before you get into a pissing match with clandestine.

 

[Moorvogi]

You really want to get on his bad side, that's cool. But I'd recommend you choose your path wisely before you get into a pissing match with clandestine.

no pissing match. he spoke his opinion, i recognized it as an opinion.