follow up shots with suppressor

[patterdale69]

hi guys im from the uk and we have used suppresors (moderators) for a lot of years. the suppresor i use i one of the lightest on the market DPT EURO, it is an over barrel type and i have no poi shift with upto 5 rounds then my light weight barrel heats up and alters poi. i have no problem shooting one after another ,we cant not have that problem as we may have 40 plus deer to shoot in one day and with most shots behind the ear we can not have a shift in poi. i use nosler accubond and use vhit powder. i have not had the pleasure of hearing the noise from a USA suppresor but i would like to no whether you you would grass 3-5 deer out of a group before they run.just a word of warning REMOVE your can after shooting, the moisture left behind is very corrosive it will damage the rifle crown and rust the can to the barrel.

 

[Ksduckhntr]

hi guys im from the uk and we have used suppresors (moderators) for a lot of years. the suppresor i use i one of the lightest on the market DPT EURO, it is an over barrel type and i have no poi shift with upto 5 rounds then my light weight barrel heats up and alters poi. i have no problem shooting one after another ,we cant not have that problem as we may have 40 plus deer to shoot in one day and with most shots behind the ear we can not have a shift in poi. i use nosler accubond and use vhit powder. i have not had the pleasure of hearing the noise from a USA suppresor but i would like to no whether you you would grass 3-5 deer out of a group before they run.just a word of warning REMOVE your can after shooting, the moisture left behind is very corrosive it will damage the rifle crown and rust the can to the barrel.

i have shot 2 does standing side by side with my suppressed rifle. After the first doe was shot, the second doe took a few steps and looked bewildered. I had a second tag so down she went too.

 

[sea2summit]

Interesting that some studies highly suggest cold bore is a Myth. They relate cold bore shift primarily to cold shooter. I've actually never had a rifle not shoot within the primary group. One we'll known shooter suggests a person warms up on a different rifle before shooting the test rifle to determine if it's the barrel or shooter. I have mixed thoughts on it but haven't found cold bore to be true for me. I like cold bore first round shots and a follow up when I practice in the field. I prefer at least 500, and like 750-1200 for practice. This target is one I did with a cold and follow up to confirm my load.

View attachment 186049

I don't think it's as big of an issue as people make it out to be, cold shooter is probably much more likely. Here's a test I did for my own amusement a while back with cold bore shots then a 5x group.

To the OPs question, these are 5x5 shot groups with a suppressed semi. Think we had 20 min to shoot because of range limitations? May have been more but it was pretty tight as I recall. Shot counter clockwise from bottom left. And it's a gasser suppressed.

 

[JoshHaker]

I have experienced the same issue. With two different rifles I have noticed my cold bore shot impacting 1.5" off from sequential shots. Could this be me?? Possibly, but the more I shoot the more I see this happening. So much so I quit hunting with mine for the time being. I will test this further.

Suppressor. Gem Tech Tracker 30 cal direct thread.

 

[SixDemonBag]

Never had this issue with my Saker 7.62 ran across several rifles in different calibers from 5.56 up 308. Supersonic and Subsonic.

I have experienced the first shot "pop" that is louder than follow on shots. Critter didn't know it was louder....

 

[brant89]

I realize I'm resurrecting an old thread, but I'm experiencing a strange first round suppressor phenomenon as well. First round with suppressor off, velocity is within normal variation. First round with suppressor on is 40fps below average. The SD of the remaining 9 shots is 10fps. I don't see any POI shift at 100 yards, but did see a dropped first round several times at 700 yards. Rifle is a 22BR, suppressor is a YHM Turbo 5.56, POI repeatability at 100 yards has been dead on, rifle has been grouping approx 1/2MOA. Anyone have any thoughts on this?

 

[BrentM]

I realize I'm resurrecting an old thread, but I'm experiencing a strange first round suppressor phenomenon as well. First round with suppressor off, velocity is within normal variation. First round with suppressor on is 40fps below average. The SD of the remaining 9 shots is 10fps. I don't see any POI shift at 100 yards, but did see a dropped first round several times at 700 yards. Rifle is a 22BR, suppressor is a YHM Turbo 5.56, POI repeatability at 100 yards has been dead on, rifle has been grouping approx 1/2MOA. Anyone have any thoughts on this?

When you did the first shot testing was it exactly the same process? I've not had the issue you describe but each system can be slightly different in how it affects the velocity. It's hard to understand how pressure forward of the bullet would create enough restriction to slow it down. Impulse wave or air pressure being held back inside the bore. Then after a shot is fired this pressure issue is somehow rectified. Can't get my head around it.

Reason I ask about the process is did you test both can and off on the same day and which was first, can on or can off? Was the test on dirty bore or clean bore?

 

[brant89]

I tested on different days, same loading process, both on a dirty bore. My only thought is that it is related to FRP and igniting the oxygen in the can. Obviously the backpressure ahead of the bullet would be the same for all shots fired, but oxygen saturation would not be. Also, the groups don't walk so I don't think it's a heat issue either. I have a lot more testing to do to confirm or debunk this theory, but it has been unusual to say the least.

 

[BrentM]

I tested on different days, same loading process, both on a dirty bore. My only thought is that it is related to FRP and igniting the oxygen in the can. Obviously the backpressure ahead of the bullet would be the same for all shots fired, but oxygen saturation would not be. Also, the groups don't walk so I don't think it's a heat issue either. I have a lot more testing to do to confirm or debunk this theory, but it has been unusual to say the least

I think your issue is carbon oxidation. Run a dry patch or 3 through the barrel before testing either and record results. There are too many variables on different test days. I'd test same day. Run a dry patch, shoot w can. Remove can. Let barrel cool for long time, I like to shoot a another rifle while it's cooling. Run a dry patch. Shoot with can off. Now have more clear picture of what is happening. If you see the same pattern then it's time to address first round velocity variation

 

[brant89]

How long does it take for carbon oxidation to occur, because I'm experiencing this during a range session. I will test suppressor on and off on the same day later this week.

 

[milo-2]

I tested on different days, same loading process, both on a dirty bore. My only thought is that it is related to FRP and igniting the oxygen in the can. Obviously the backpressure ahead of the bullet would be the same for all shots fired, but oxygen saturation would not be. Also, the groups don't walk so I don't think it's a heat issue either. I have a lot more testing to do to confirm or debunk this theory, but it has been unusual to say the least.

I would point towards the suppressor itself. Wasn't first shot repeatability one of the biggest advertising claims from TBAC? If you could test a different can on the rifle, questions may be answered.
On the oxygen theory, atmospheric air doesn't really ignite, if you injected pure oxygen in the can and barrel things may get funky.
As for daily carbon oxidation, not sure I am buying into that either, I think i would start by stripping the barrel clean, fire 10 fouling shots one day, come back the next and run this test.
Not all suppressors are created equally, I see that in the brands I own.

 

[BrentM]

How long does it take for carbon oxidation to occur, because I'm experiencing this during a range session. I will test suppressor on and off on the same day later this week.

A week or 2. Depends on how dirty the powder is you are using etc.

If you are doing the test on the same day same range session then you've answer the questions. I was under the impression it was different days.

 

[BrentM]

I would point towards the suppressor itself. Wasn't first shot repeatability one of the biggest advertising claims from TBAC? If you could test a different can on the rifle, questions may be answered.
On the oxygen theory, atmospheric air doesn't really ignite, if you injected pure oxygen in the can and barrel things may get funky.
As for daily carbon oxidation, not sure I am buying into that either, I think i would start by stripping the barrel clean, fire 10 fouling shots one day, come back the next and run this test.
Not all suppressors are created equally, I see that in the brands I own.

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.

 

[brant89]

I would point towards the suppressor itself. Wasn't first shot repeatability one of the biggest advertising claims from TBAC? If you could test a different can on the rifle, questions may be answered.
On the oxygen theory, atmospheric air doesn't really ignite, if you injected pure oxygen in the can and barrel things may get funky.
As for daily carbon oxidation, not sure I am buying into that either, I think i would start by stripping the barrel clean, fire 10 fouling shots one day, come back the next and run this test.
Not all suppressors are created equally, I see that in the brands I own.

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.