Short barrel cartridge help!

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,320
Location
Meridian, Idaho
If your running suppressed you can treat the length of your can as extra barrel inches. A 20” barrel with a 6” suppressor should run pretty much like a 24-26” barrel would. You shouldn’t loose to much velocity. For your application I would probably go 7 SAUM.
I've never seen any real noteworthy increase in velocity. There is NO additional pressure being created therefore there is no additional speed generated.
 
Last edited:

lancetkenyon

Well-Known Member
Joined
Jun 3, 2013
Messages
4,059
Location
Arizona
If your running suppressed you can treat the length of your can as extra barrel inches. A 20” barrel with a 6” suppressor should run pretty much like a 24-26” barrel would. You shouldn’t loose to much velocity. For your application I would probably go 7 SAUM.
How many suppressors have you run that pick up 100-150+fps?

I run cans on 8 rifles currently, and the difference between unsuppressed and suppressed is between 12-25fps. From 6.5", to 7", to 9" cans, the can length makes zero difference in my velocities with the same rifle/load combo.

I have a 20" and a 26" 6.5SS. With the EXACT same load, in the 20" suppressed, it is 130fps slower than the 26" unsuppressed. And 149fps slower when both are suppressed with the same can.
 
Last edited:

vancewalker007

Well-Known Member
Joined
Mar 30, 2013
Messages
684
How many suppressors have you run that pick up 100-150+fps?

I run cans on 8 rifles currently, and the difference between unsuppressed and suppressed is between 12-25fps. From 6.5", to 7", to 9" cans, the can length makes zero difference in my velocities with the same rifle/load combo.
Its funny, I brought this question up with Gunwerks to understand their experience. Their response was the suppressors they have used don't add and significant velocity versus having the can off. This is 1000s of rounds of experience talking. I think its commonly passed around Bro Science that this happens. I could see a POI change from the weight.
 

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,320
Location
Meridian, Idaho
Its funny, I brought this question up with Gunwerks to understand their experience. Their response was the suppressors they have used don't add and significant velocity versus having the can off. This is 1000s of rounds of experience talking. I think its commonly passed around Bro Science that this happens. I could see a POI change from the weight.

Often see people zero without the can and then hit high using a can with the same zero. They assume the velocity is higher due to impact point. It has nothing to do with speed, but they don't know that. Same thing happens with swapping around factory ammo and using same aim point. Just a lack of understanding impact point at zero is more a function of barrel time.
 

simmonzz

Well-Known Member
Joined
May 21, 2021
Messages
94
Location
Oregon
16.5. 6.5 saum should still be faster than long barrel Creed speeds. I've got a 19inch GAP4's sending 139's at 3030fps
I'm planning on shooting 124 hammers, 131 hammers or 129 absolute hammers depending on how fast it ends up shooting. thats good to know tho thanks!
 

simmonzz

Well-Known Member
Joined
May 21, 2021
Messages
94
Location
Oregon
If your running suppressed you can treat the length of your can as extra barrel inches. A 20” barrel with a 6” suppressor should run pretty much like a 24-26” barrel would. You shouldn’t loose to much velocity. For your application I would probably go 7 SAUM.
that's definitely not true. a suppressor can and seems to add roughly 15-20fps in my experiences not 25-50fps per inch
 

436

Well-Known Member
Joined
Mar 22, 2009
Messages
1,308
Location
NorthWest
that's definitely not true. a suppressor can and seems to add roughly 15-20fps in my experiences not 25-50fps per inch
Agree, 👍 you will always get some backpressure which means a slight jump in velocity. I don't think I've ever shot one that didn't. Just my 0.2
 
Last edited:

Paladin300

Well-Known Member
LRH Team Member
Joined
Aug 24, 2020
Messages
262
Location
Alabama
How many suppressors have you run that pick up 100-150+fps?

I run cans on 8 rifles currently, and the difference between unsuppressed and suppressed is between 12-25fps. From 6.5", to 7", to 9" cans, the can length makes zero difference in my velocities with the same rifle/load combo.

I have a 20" and a 26" 6.5SS. With the EXACT same load, in the 20" suppressed, it is 130fps slower than the 26" unsuppressed. And 149fps slower when both are suppressed with the same can.
You loose approximately 25 fps for every inch of barrel you cut off. That is standardized across all cartridges. Some will loose more, some less but that is a good rule of thumb. Every rifle is different. I have a 18” 7mm-08 that unsurpressed will shoot 150s at 2650 with a break. If we try to push them any fast we run into issues with the unburnt powder. With a 6” suppressor on we are getting just over 2700. The suppressor allows us to turn it up a little more without accuracy issues. After we do that with a few more grains off powder we are right around 2750, which is essentially what you would get out of a 22-24” rifle in the same caliber. I should have qualified my statement more. I run 42.5 grains unsuppressed which is the max I can get and maintain accuracy and the suppressor allows me to run 45.2 grains, which is the same load I can run in a 24” barrel but not in an 18”. Neither loads show any signs of pressure but the heavier load won’t shoot without the can.
You are correct however that the difference in the can or without it is only about 25-50fps with identical loads.
 

WeiserBucks

Well-Known Member
Joined
Aug 16, 2016
Messages
1,862
You loose approximately 25 fps for every inch of barrel you cut off. That is standardized across all cartridges. Some will loose more, some less but that is a good rule of thumb. Every rifle is different. I have a 18” 7mm-08 that unsurpressed will shoot 150s at 2650 with a break. If we try to push them any fast we run into issues with the unburnt powder. With a 6” suppressor on we are getting just over 2700. The suppressor allows us to turn it up a little more without accuracy issues. After we do that with a few more grains off powder we are right around 2750, which is essentially what you would get out of a 22-24” rifle in the same caliber. I should have qualified my statement more. I run 42.5 grains unsuppressed which is the max I can get and maintain accuracy and the suppressor allows me to run 45.2 grains, which is the same load I can run in a 24” barrel but not in an 18”. Neither loads show any signs of pressure but the heavier load won’t shoot without the can.
You are correct however that the difference in the can or without it is only about 25-50fps with identical loads.
What brand is this magic suppressor? I want to buy one or twenty.
 

Paladin300

Well-Known Member
LRH Team Member
Joined
Aug 24, 2020
Messages
262
Location
Alabama
What brand is this magic suppressor? I want to buy one or twenty.
It’s a form 1 titanium suppressor we built a few years back. Nothing special. Here it is on a 10” SBR I own. I don’t have a pic of it on the 7mm. One of the reasons we maybe seeing a little more than usual velocity maybe owed to the fact that the baffles don’t actually start for about an inch to an inch and a half inside the suppressor resulting in about 5”s of baffles and therefore acting like a 1-2” barrel extension. Watch this video of Larry Vickers shooting suppressed. Last 7-8 minutes. They experienced the same thing and picked up approximately 100yards extra suppressed. In case your wondering that is about 100-200 fps to gain that much distance at that range. Like guns all suppressors are not equal. I have a couple of 270s that are set up identically to each other and they shoot the same ammo about 50 fps apart. Barrels and suppressors matter. Mine is a mono core design not individual baffles, but the biggest issue to me is being able to push the loads a little more than you can unsupressed out of a short barreled rifle. This may not be everyone’s experience but it has been mine but I have exactly a sample of one.
052C066C-A6F7-472A-8EDE-84C9A792DC97.jpeg
83F2673F-6BFB-4CB0-AD84-8ACD743D3BBA.jpeg
 
Last edited:

shootski

Well-Known Member
Joined
May 24, 2018
Messages
63
Location
Arlington, Virginia
In anticipation of getting my first suppressor soon, I’m realizing I only have one rifle currently with a short barrel that will make running a suppressor not awkward due to a very long barrel after suppressor installation. I might end up selling a couple rifles and doing another build. I would want a do it all type cartridge for up to elk size game out to 800 yds or so. Leaning 7saum or 6.5PRC. Had a buddy recommend 284win as well. Thoughts? Already have a 24” barreled 300wsm that’s not going anywhere.
I have got to ask this. IF you are shooting a supersonic round why are you using a suppressor? Hearing protection I sort of understand but as for the rest I don't get it.

I hunt subsonic and use a suppressor so understand I'm not opposed to suppression while hunting.

Looking for some learning here.
 

simmonzz

Well-Known Member
Joined
May 21, 2021
Messages
94
Location
Oregon
It’s a form 1 titanium suppressor we built a few years back. Nothing special. Here it is on a 10” SBR I own. I don’t have a pic of it on the 7mm. Watch this video of Larry Vickers shooting suppressed. Last 7-8 minutes. They experienced the same thing and picked up approximately 100yards extra suppressed. In case your wondering that is about 100-200 fps to gain that much distance at that range. Like guns all suppressors are not equal. I have a couple of 270s that are set up identically to each other and they shoot the same ammo about 50 fps apart. Barrels and suppressors matter. Mine is a mono core design not individual baffles, but the biggest issue to me is being able to push the loads a little more than you can unsupressed out of a short barreled rifle. This may not be everyone’s experience but it has been mine but I have exactly a sample of one.View attachment 316207View attachment 316212

That makes a little more sense but to say the suppressor adds the extra velocity still isn’t and wasn’t true. Suppressors can and usually do tighten up groups but the only reason you’re getting higher velocities is because you’re adding more powder. It’s definitely not the suppressor adding the velocity if you chrono’ dot with/without the can regardless of group size it’d be around the 10-20fps people typically see.
 

simmonzz

Well-Known Member
Joined
May 21, 2021
Messages
94
Location
Oregon
I have got to ask this. IF you are shooting a supersonic round why are you using a suppressor? Hearing protection I sort of understand but as for the rest I don't get it.

I hunt subsonic and use a suppressor so understand I'm not opposed to suppression while hunting.

Looking for some learning here.
A suppressor especially on a short barreled rifle is going to take a considerable amount of bark out of the gun, reduce recoil to a degree like a brake would and typically tighten up groups and make it much more pleasant to shoot and keep your ears from ringing. Just because the round is going faster than the speed of sound doesn’t mean the decibels entering the shooters ear still can’t be reduced to a much safer level. I hunt suppressed so I don’t have to use ear pro or have a brake on my gun that makes it even louder
 
Top