(Thread Closed, Thanks Everyone!) Reloading Subsonic AR-10 that CYCLES 265grain 308 Quick load?

[casualfornow]

A new twist on reloading Subsonic AR-10 that CYCLES?

What is currently made: Atomic Tactical Cycling Subsonic Ammunition 308 Winchester 260 Grain Expanding Round Nose Soft Point $122 a box (not in stock)

What about ACME 30cal.309 265gr 300 BLKOUT BULLET COATED $.30 each with Trail Boss powder? Is Trail Boss the right choice for the limited case capacity?

Can anyone calculate a load for this at 1050fps? Or is it simply not practical or possible?

Thanks.

 

[redbullitt]

Probably going to depend heavily on gas system and bcg/buffer. Normally thats a pretty tall order unless rifle is dedicated to subs not a full power tuned 308. I have not tried that ammo though to be fair.

I shoot a 250ish grain cast bullet a lot in blackouts for subs . It can be made to run super and subs pretty well with the same settings/same gun but even thats not optimal.

My 308 gasser is another animal, but to be fair i only tinkered in passing to do it. I ended up running it manually, shot well. Trail boss makes fantastic 308 subs, but it will not run a normal gas gun, far too fast burning and low gas.

Powders that are gassy like lilgun, cfeblk, 1680 etc all work well with reduced capacity of the 300 blk and a semi auto, but 308 will have a lot of empty space in there, no good. I will say cfeblk runs the 300blk down way lower speed than anything else ive seen, but again doubtful to be a good choice in a big 308 case.

Reduced capacity 308 cases, pain in the ass, could help greatly, but not a normal thing at all to find.

IF you allow for the rifle to be charged manually after firing, this having it shoot quietly and well is very doable with trailboss etc. Otherwise itll be very tough to say the least.

 

[Hecouldgoalltheway]

This seems like a good way to have a 3" long bullet wedged into your rifling. I didn't know anyone made a .308 sub designed to cycle. It is very interesting.

 

[Yondering]

A new twist on reloading Subsonic AR-10 that CYCLES?

What is currently made: Atomic Tactical Cycling Subsonic Ammunition 308 Winchester 260 Grain Expanding Round Nose Soft Point $122 a box (not in stock)

What about ACME 30cal.309 265gr 300 BLKOUT BULLET COATED $.30 each with Trail Boss powder? Is Trail Boss the right choice for the limited case capacity?

Can anyone calculate a load for this at 1050fps? Or is it simply not practical or possible?

Thanks.

I think you're missing quite a bit of understanding about operation of the gas system and what's required for the rifle to cycle, relative to different powders & burn rates, pressure relative to case volume, etc.

If you want to make a subsonic load in a bolt action or single shot - that Trail Boss powder is great. Lots of people use it for that, in a bunch of different cartridges.

But that load will be nowhere close to cycling your AR-10. Not even remotely. In fact if you want to make your AR-10 quieter by not cycling the action, Trail Boss is an excellent choice; you'll need to cycle the action by hand every shot but will eliminate the port noise.

To cycle the action, a heavy bullet like that helps (and isn't a new twist, that weight and heavier have been around a long time now) but you need a powder that produces a LOT more gas volume and maintains more pressure out at the gas port (which is way farther down the barrel than where/when peak pressure occurs), while also keeping the round subsonic. That's a tall order in a larger case like the 308, and doubly/triply true in the heavier 308 operating system. There is a BIG reason why successful subsonic rounds use small cases.

I have made reduced capacity subsonic cases by filling most of the case volume with lead, but use them for manually operated actions. Even if you did this, you'll still be fighting that heavy AR10 operating system.

In all honesty - this is why the 300 Blk exists. It's already got the faster twist rate you need to stabilize that bullet (your 1:10 308 does not), it's a tiny case optimized for subsonics with bullets like this, and the lighter AR15 operating system is much easier to cycle. You'll be way ahead to just buy a 300 Blk for subsonics and forget the 308.

 

[Hecouldgoalltheway]

I think you're missing quite a bit of understanding about operation of the gas system and what's required for the rifle to cycle, relative to different powders & burn rates, pressure relative to case volume, etc.

If you want to make a subsonic load in a bolt action or single shot - that Trail Boss powder is great. Lots of people use it for that, in a bunch of different cartridges.

But that load will be nowhere close to cycling your AR-10. Not even remotely. In fact if you want to make your AR-10 quieter by not cycling the action, Trail Boss is an excellent choice; you'll need to cycle the action by hand every shot but will eliminate the port noise.

To cycle the action, a heavy bullet like that helps (and isn't a new twist, that weight and heavier have been around a long time now) but you need a powder that produces a LOT more gas volume and maintains more pressure out at the gas port (which is way farther down the barrel than where/when peak pressure occurs), while also keeping the round subsonic. That's a tall order in a larger case like the 308, and doubly/triply true in the heavier 308 operating system. There is a BIG reason why successful subsonic rounds use small cases.

I have made reduced capacity subsonic cases by filling most of the case volume with lead, but use them for manually operated actions. Even if you did this, you'll still be fighting that heavy AR10 operating system.

In all honesty - this is why the 300 Blk exists. It's already got the faster twist rate you need to stabilize that bullet (your 1:10 308 does not), it's a tiny case optimized for subsonics with bullets like this, and the lighter AR15 operating system is much easier to cycle. You'll be way ahead to just buy a 300 Blk for subsonics and forget the 308.

Or buy an 8.6 blackout barrel. They seem to have that system figured out.

 

[casualfornow]

Probably going to depend heavily on gas system and bcg/buffer. Normally thats a pretty tall order unless rifle is dedicated to subs not a full power tuned 308. I have not tried that ammo though to be fair.

I shoot a 250ish grain cast bullet a lot in blackouts for subs . It can be made to run super and subs pretty well with the same settings/same gun but even thats not optimal.

My 308 gasser is another animal, but to be fair i only tinkered in passing to do it. I ended up running it manually, shot well. Trail boss makes fantastic 308 subs, but it will not run a normal gas gun, far too fast burning and low gas.

Powders that are gassy like lilgun, cfeblk, 1680 etc all work well with reduced capacity of the 300 blk and a semi auto, but 308 will have a lot of empty space in there, no good. I will say cfeblk runs the 300blk down way lower speed than anything else ive seen, but again doubtful to be a good choice in a big 308 case.

Reduced capacity 308 cases, pain in the ass, could help greatly, but not a normal thing at all to find.

IF you allow for the rifle to be charged manually after firing, this having it shoot quietly and well is very doable with trailboss etc. Otherwise itll be very tough to say the least.

Thanks so much for the heads up! I saw atomic produced ammo that supposedly works I thought perhaps we could duplicate it. Appreciate your time.

 

[casualfornow]

This seems like a good way to have a 3" long bullet wedged into your rifling. I didn't know anyone made a .308 sub designed to cycle. It is very interesting.

I saw atomic ammo making something they claim to cycle I thought perhaps we could duplicate it.

 

[casualfornow]

I think you're missing quite a bit of understanding about operation of the gas system and what's required for the rifle to cycle, relative to different powders & burn rates, pressure relative to case volume, etc.

If you want to make a subsonic load in a bolt action or single shot - that Trail Boss powder is great. Lots of people use it for that, in a bunch of different cartridges.

But that load will be nowhere close to cycling your AR-10. Not even remotely. In fact if you want to make your AR-10 quieter by not cycling the action, Trail Boss is an excellent choice; you'll need to cycle the action by hand every shot but will eliminate the port noise.

To cycle the action, a heavy bullet like that helps (and isn't a new twist, that weight and heavier have been around a long time now) but you need a powder that produces a LOT more gas volume and maintains more pressure out at the gas port (which is way farther down the barrel than where/when peak pressure occurs), while also keeping the round subsonic. That's a tall order in a larger case like the 308, and doubly/triply true in the heavier 308 operating system. There is a BIG reason why successful subsonic rounds use small cases.

I have made reduced capacity subsonic cases by filling most of the case volume with lead, but use them for manually operated actions. Even if you did this, you'll still be fighting that heavy AR10 operating system.

In all honesty - this is why the 300 Blk exists. It's already got the faster twist rate you need to stabilize that bullet (your 1:10 308 does not), it's a tiny case optimized for subsonics with bullets like this, and the lighter AR15 operating system is much easier to cycle. You'll be way ahead to just buy a 300 Blk for subsonics and forget the 308.

Thanks for the lesson and insight. I appreciate it. Look like atomic made something that cycles I thought we could perhaps duplicate it. Yes maybe 8.6.

 

[redbullitt]

Theres a good chance IF those factory made rounds work they are using a powder we may not have access to.

It would be very cool if it works. Ive played a lot with sub and reduced loads, and from what I've seen that is a a tough order.

The blackout rounds all have proper capacity for lower speeds. They will all do a nice job.

 

[casualfornow]

Probably going to depend heavily on gas system and bcg/buffer. Normally thats a pretty tall order unless rifle is dedicated to subs not a full power tuned 308. I have not tried that ammo though to be fair.

I shoot a 250ish grain cast bullet a lot in blackouts for subs . It can be made to run super and subs pretty well with the same settings/same gun but even thats not optimal.

My 308 gasser is another animal, but to be fair i only tinkered in passing to do it. I ended up running it manually, shot well. Trail boss makes fantastic 308 subs, but it will not run a normal gas gun, far too fast burning and low gas.

Powders that are gassy like lilgun, cfeblk, 1680 etc all work well with reduced capacity of the 300 blk and a semi auto, but 308 will have a lot of empty space in there, no good. I will say cfeblk runs the 300blk down way lower speed than anything else ive seen, but again doubtful to be a good choice in a big 308 case.

Reduced capacity 308 cases, pain in the ass, could help greatly, but not a normal thing at all to find.

IF you allow for the rifle to be charged manually after firing, this having it shoot quietly and well is very doable with trailboss etc. Otherwise itll be very tough to say the least.

Theres a good chance IF those factory made rounds work they are using a powder we may not have access to.

It would be very cool if it works. Ive played a lot with sub and reduced loads, and from what I've seen that is a a tough order.

The blackout rounds all have proper capacity for lower speeds. They will all do a nice job.

I agree with you. It does appear to be a tough order. Thanks for your feedback!

 

[redbullitt]

Sure thing! i doubt it will be cost work or time effective to modify your rifle to do it when the blk cartridges do such a good job off the shelf.

I have seen some need ar15s set up for subs running fast pistol powders normally used in bolt guns, but again totally niche situation and not a good platform for supersonics unless using some kind of custom switchable gas.

 

[casualfornow]

Sure thing! i doubt it will be cost work or time effective to modify your rifle to do it when the blk cartridges do such a good job off the shelf.

I have seen some need ar15s set up for subs running fast pistol powders normally used in bolt guns, but again totally niche situation and not a good platform for supersonics unless using some kind of custom switchable gas.

Thanks for the heads up. I appreciate it!

 

[TexasHaag]

A new twist on reloading Subsonic AR-10 that CYCLES?

What is currently made: Atomic Tactical Cycling Subsonic Ammunition 308 Winchester 260 Grain Expanding Round Nose Soft Point $122 a box (not in stock)

What about ACME 30cal.309 265gr 300 BLKOUT BULLET COATED $.30 each with Trail Boss powder? Is Trail Boss the right choice for the limited case capacity?

Can anyone calculate a load for this at 1050fps? Or is it simply not practical or possible?

Thanks.

Greetings, I tried for months to work up a 308 subsonic load for my AR10. Between myself and a friend trying to do the same thing we used a dozen different powders and at least that many different bullets. We adjusted gas blocks, reduced weight and tension of the buffer.... we never were able to get a load to run in either gas gun... having exhausted efforts, we decided the .308 was not designed to go subsonic. Pick a cartridge that is designed to load subsonic.
texashaag...

 

[casualfornow]

Greetings, I tried for months to work up a 308 subsonic load for my AR10. Between myself and a friend trying to do the same thing we used a dozen different powders and at least that many different bullets. We adjusted gas blocks, reduced weight and tension of the buffer.... we never were able to get a load to run in either gas gun... having exhausted efforts, we decided the .308 was not designed to go subsonic. Pick a cartridge that is designed to load subsonic.
texashaag...

Thanks so much TexasHaag. I appreciate the the feedback. I'm sure you saved me a bunch of time and effort. Have a great week!

 

[TexasHaag]

A new twist on reloading Subsonic AR-10 that CYCLES?

What is currently made: Atomic Tactical Cycling Subsonic Ammunition 308 Winchester 260 Grain Expanding Round Nose Soft Point $122 a box (not in stock)

What about ACME 30cal.309 265gr 300 BLKOUT BULLET COATED $.30 each with Trail Boss powder? Is Trail Boss the right choice for the limited case capacity?

Can anyone calculate a load for this at 1050fps? Or is it simply not practical or possible?

Thanks.

Where will you get the powder Trail Boss?

 

[casualfornow]

Where will you get the powder Trail Boss?

 

[casualfornow]

I think I saw some at my local sportsman's warehouse. Be a little resourceful and you can find it. Or just try gunbroker.com

 

[Mike_in_FL]

I think I saw some at my local sportsman's warehouse. Be a little resourceful and you can find it. Or just try gunbroker.com

I was just reading a little about .308 subs today using Trail Boss. I don't think you can get it to cycle unless you build a subs only gun.

https://www.ammoland.com/2022/11/subsonic-308-win-handloads/