follow up shots with suppressor

[milo-2]

I think he has a yhm can not a tbac. Mine is tbac and I've killed yotes and wolves from 500 out to 1125 yards this year and haven't seen a 40 FPS deviation. Not sure what others have experienced with tbac but I can not find accuracy faults with mine. I never shoot without it and it does a fine job. Low es, low sd, and repeatable in all conditions I've been in. Most people I know run tbac or omega so I don't see much else.

I had read what he was using, So we are in agreement that the can itself could be the culprit. I steered away from SiCo, but a friend bought 2, I like them now.

 

[milo-2]

I maybe "igniting the oxygen" isn't the best wording, but FRP is pretty well documented. What's perplexing to me is that my first round POI at close distances falls right into the rest of the group and the groups are pretty small. Maybe it's just me the shooter, but I found it strange that I dropped my first round 1MOA low at 700 yards followed by 4 more shots that were sub-MOA and printed several 1/2-3/4 MOA groups at that distance later that day, but some of the first rounds were errant (hard to spot anything off steel in the snow). Then the chronograph data I took later supported the first round velocity theory. Again, no first round POI shift at 100yards.

OK, I get it now, what you are saying is the can needs to fill with smoke before becoming effective. Cold bore can occur with non and suppressed barrels, there may be no way to minimize yours.

 

[brant89]

I had read what he was using, So we are in agreement that the can itself could be the culprit. I steered away from SiCo, but a friend bought 2, I like them now.

I understand I'm not running a high-end can and I'm not expecting high-end performance like a TBAC or SiCo. That being said, the results are still pretty odd when the rifle shoots extremely well with the can on. No change in POI when I take the can off and back on again, which I do frequently.

 

[brant89]

OK, I get it now, what you are saying is the can needs to fill with smoke before becoming effective. Cold bore can occur with non and suppressed barrels, there may be no way to minimize yours.

It's my understanding that FRP is related to oxygen levels in the can rather than smoke particulate. That's why flushing the suppressor with canned air or shooting it "wet" will significantly reduce or eliminate FRP, but correct me if I'm wrong. It could be a cold bore issue I suppose. Could the cold bore affect only the velocity and not POI at 100yd?

 

[milo-2]

It could be a cold bore issue I suppose. Could the cold bore affect only the velocity and not POI at 100yd?

I believe so, 100 yards not far. I did not call your product subpar, just said differences in products.
I have 6 suppressors sitting idle, not worth the noise gains.
Tale: A lot of guys took to running 223 cans on small 6mm cases, BR, Dasher's, etc... Lane brand is popular in my region, and guys use their Lane's for this, I have the same can, you think I can get over 15 shots off before my bolt locks up, no I can't. Shooting right beside virtually the same, mine won't cut it.
I am not saying you are overthinking this, but I don't think your issue is unique.

 

[brant89]

I believe so, 100 yards not far. I did not call your product subpar, just said differences in products.
I have 6 suppressors sitting idle, not worth the noise gains.
Tale: A lot of guys took to running 223 cans on small 6mm cases, BR, Dasher's, etc... Lane brand is popular in my region, and guys use their Lane's for this, I have the same can, you think I can get over 15 shots off before my bolt locks up, no I can't. Shooting right beside virtually the same, mine won't cut it.
I am not saying you are overthinking this, but I don't think your issue is unique.

Your bolt locks up after 15 rounds due to the suppressor? This is my first time running a can on a precision rifle so I'm fairly new to the long-range performance aspects of suppressed shooting. My carbine isn't precise enough for any of this stuff to ever be noticeable.

 

[orifdoc]

I'd remove the can and fire a bunch of groups to see what the rifle is doing without it. After that, I'd be suspicious of the mounting mechanism. Direct thread can be better than quick-connect options. The guys I hunt with use direct-thread and they screw them on TIGHT because they've had occasional issues. They do lots of culling and are often shooting 20-30 animals a day. The Ultra 9 is a big, heavy can and if you get a bit of thread movement from first-shot recoil it could affect your POI a little.

I use an Ultra 5 on a .300 WM and I've not seen any issues as severe as you describe. I do get an interesting, reproducible shift in my POI between shots 1&2. 2&3 are usually close together, but it's all inside 1/2 MOA (sometimes 1/4 MOA) so it doesn't bother me. This year I did have to take a follow-up shoot on a mulie buck. It happens. Thank goodness shot #2 cleaned it up.

And now I see the OP is from 2020.

 

[brant89]

I'd remove the can and fire a bunch of groups to see what the rifle is doing without it. After that, I'd be suspicious of the mounting mechanism. Direct thread can be better than quick-connect options. The guys I hunt with use direct-thread and they screw them on TIGHT because they've had occasional issues. They do lots of culling and are often shooting 20-30 animals a day. The Ultra 9 is a big, heavy can and if you get a bit of thread movement from first-shot recoil it could affect your POI a little.

I use an Ultra 5 on a .300 WM and I've not seen any issues as severe as you describe. I do get an interesting, reproducible shift in my POI between shots 1&2. 2&3 are usually close together, but it's all inside 1/2 MOA (sometimes 1/4 MOA) so it doesn't bother me. This year I did have to take a follow-up shoot on a mulie buck. It happens. Thank goodness shot #2 cleaned it up.

And now I see the OP is from 2020.

I'm going to run 5 rounds over the Magnetospeed unsuppressed, then 5 rounds suppressed and see if the first round of each set is a lower velocity or not. That would confirm the cold bore theory vs FRP theory. If it's related to cold bore then the first round unsuppressed should be slower, if it's the suppressor then the first round suppressed should be slower.

 

[milo-2]

Your bolt locks up after 15 rounds due to the suppressor? This is my first time running a can on a precision rifle so I'm fairly new to the long-range performance aspects of suppressed shooting. My carbine isn't precise enough for any of this stuff to ever be noticeable.

Take it off and run a brake, no hiccups. I assume here.

 

[milo-2]

It's my understanding that FRP is related to oxygen levels in the can rather than smoke particulate. That's why flushing the suppressor with canned air or shooting it "wet" will significantly reduce or eliminate FRP, but correct me if I'm wrong. It could be a cold bore issue I suppose. Could the cold bore affect only the velocity and not POI at 100yd?

Lol, now if I owned a grenade launcher, and a supply of fun, I would "prime" one of those, not a can.

 

[brant89]

Well to update everyone, I guess I'm chasing ghosts and I need to work on that "cold shooter" POI shift. Here's the data...

Unsuppressed:
2926
2901
2904
2896
2894
Avg - 2904, ES - 32, SD 12

Suppressed:
2949
2925
2926
2925
2935
Avg - 2932, ES - 24, SD - 10

First round was 28 and 22 faster than the average of the following four rounds for each set respectively (suggesting approx 25 fps first round jump) and the ES and SD drops to 10 and 4 for both data sets if you disregard the cold bore.

 

[brant89]

Well to update everyone, I guess I'm chasing ghosts and I need to work on that "cold shooter" POI shift. Here's the data...
Unsuppressed:
2926
2901
2904
2896
2894
Avg - 2904, ES - 32, SD 12

Suppressed:
2949
2925
2926
2925
2935
Avg - 2932, ES - 24, SD - 10
First round was 27 and 22 faster than the average of the following four rounds (suggesting a 25 fps first round jump) and the ES

 

[milo-2]

Well to update everyone, I guess I'm chasing ghosts and I need to work on that "cold shooter" POI shift. Here's the data...

Unsuppressed:
2926
2901
2904
2896
2894
Avg - 2904, ES - 32, SD 12

Suppressed:
2949
2925
2926
2925
2935
Avg - 2932, ES - 24, SD - 10

First round was 28 and 22 faster than the average of the following four rounds for each set respectively (suggesting approx 25 fps first round jump) and the ES and SD drops to 10 and 4 for both data sets if you disregard the cold bore.

Now the first shot is faster, rather than 40 fps slower? Not a hunter, cold bore is never a thing, myself and all my friends start a range day with a shot at a 10" pc of steel at 500 yards, usually hits, it's like a buy in.
Then go about our business.

 

[brant89]

I also noticed today that the magnetospeed will slip on the suppressor since I had to remove the rubber spacers to get the bayonet close enough to the bore which gave me some really crazy velocity swings. I mean impossible velocity swings, like 500fps. So this could account for the lower velocity with the previous test. I used a rubber band under the bayonet this time so it couldn't slip.