Interesting group results, lots of questions

GBMaryland

GBMaryland

Herr Oberst
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    • Feb 24, 2008
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    Maryland, US
    #1
    Here’s the situation:

    Picked up a PVA osprey 6 Creedmoor 1:7 barrel with what should be a standard chamber.

    I’ve been testing various factory ammunition to see how well it works, and I ran into an interesting issue with Barnes 112gr rounds.

    On a cold gun while taking my time to shoot, I got this:

    IMG_2796.jpeg


    With a very warm gun and deciding, I didn’t give a crap anymore, I got this shooting rapid fire (it’s probably more like timed fire and so far speed was concerned… cycle bolt, aim, fire, cycle bolt aim fire…):

    IMG_2797.jpeg


    What I did notice was that I shot fairly well 20 rounds for the second set and I definitely ended up with a grouping.

    I filed it under interesting, but then I started thinking:

    - Cold barrel initially, warm barrel for the second string
    - Abel Thorium-L vs thunder beast ultra9 for the second string

    Can either of those things significantly affect the groups?

    I would not expect either of those cans to do anything but make things shoot better.

    Other ammunition does tend to work very well in that rifle… the 112gr ammo has shown to not do such a great job… at least initially. 110ATips shoot very well, as do a variety of ELDM and Berger rounds
     
    #5
    GBMaryland said:
    Here’s the situation:

    Picked up a PVA osprey 6 Creedmoor 1:7 barrel with what should be a standard chamber.

    I’ve been testing various factory ammunition to see how well it works, and I ran into an interesting issue with Barnes 112gr rounds.

    On a cold gun while taking my time to shoot, I got this:

    View attachment 8533895

    With a very warm gun and deciding, I didn’t give a crap anymore, I got this shooting rapid fire (it’s probably more like timed fire and so far speed was concerned… cycle bolt, aim, fire, cycle bolt aim fire…):

    View attachment 8533896

    What I did notice was that I shot fairly well 20 rounds for the second set and I definitely ended up with a grouping.

    I filed it under interesting, but then I started thinking:

    - Cold barrel initially, warm barrel for the second string
    - Abel Thorium-L vs thunder beast ultra9 for the second string

    Can either of those things significantly affect the groups?

    I would not expect either of those cans to do anything but make things shoot better.

    Other ammunition does tend to work very well in that rifle… the 112gr ammo has shown to not do such a great job… at least initially. 110ATips shoot very well, as do a variety of ELDM and Berger rounds
    Click to expand...
    I'm betting the can. Go shoot it with the U9 cold bore and see what results you get.
     
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    #6
    Different cans, different mounts, different weights all play a factor. Your barrel is like a tuning fork. Change in tune produces different results

    If it doesn’t like 112 as much as the others I’d just set that aside and rule it out.

    My TBAC U9 has zero negative impacts on any gun I’ve shot it with. I have yet to test a rifle in 6.5/308 calibers where it hurt accuracy vs bare muzzle or brake. That’s probably 6-8 guns or barrels I’ve used it on
     
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    Reactions: diggler1833 and D̷e̷v̷i̷l̷D̷o̷c̷A̷Z̷
    #8
    Many possibilities one of them is bad trigger pull, shooting slow you may be disturbing the rifle as the
    trigger releases the sear. Rapid fire you are probably slapping the trigger disturbing the rifle less.
     
    #9
    Yeah any suppressor weight or adapter weight will play with harmonics. If you have ill effects from a suppressor or any other muzzle device. It’s possible that the threads are not centric by a small margin. I dont know I had pva prefit that I could not get to shoot consistently. Kinda turned me off the whole prefit thing. Plenty of people have good luck tho. My Smith spun up a bartlien and it’s night and day.
     
    #10
    I went back out and I did some test firings yesterday.

    I will say that the rifle seems to be very sensitive to certain loads, even if it’s factory ammo.

    Interestingly, federal gold medal match 107 Sierra match King ammo shot one ragged hole at 100 yards.

    The rifle definitely does not love 112 grain burger, and other ammo shot OK… just not exceptional

    I was trading on an off between the two suppressors to see if there was a difference, but the thunder beast and the Abel had the same POI.
     
    Last edited:
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    #11
    I have noticed that some bullets require a lot more fiddling with to get to shoot well, while others shoot phenomenally almost across the powder and depth range...and it is barrel specific (no two are alike). I've got a 1:7.25 AI barrel in 6CM that will shoot the 107 SMK pretty well with a lot of load development - and it shoots the 108 ELD-M amazingly across a full two grains of powder and .025 seating depth. I might chalk some of the OP's experience to this.

    +1 on the weight of muzzle devices effecting barrel harmonics. Coupled with a bullet that is pickier in a particular barrel, I would expect that the swings in consistency might be a bit more pronounced.
     
    #12
    My initial thought is you have a sensitive barrel. Not saying it’s “bad”, but it’s not a “good” barrel. I have had a few over the years that would shoot well within the acceptable range (yes I am very picky), but we’re not exactly anything to brag about. These barrels required a very specific load, normally I was never able to get the expected velocity for the caliber / bullet / barrel specs and the accuracy. If I remember correctly I had to come off my “normal velocity range” around 100fps or more to get the expected accuracy. IMO accuracy changes in relation to barrel heat the main suspect is stress in the metal, with the second a machining / fit (barrel to action, ammo to chamber, bullet to bore). I don’t see a suppressor or any muzzle device (pending properly installed / fit) causing an accuracy change correlated with heat.

    I am interested to know what comes of this. I hope all is well with you and yours my friend - Jesse
     
    #13
    You know, Herr Bell, I think you were probably right about this barrel. It’s a PVA osprey, and it is really interesting that the 107 grain federal gold medal match shoots fantastic, but some of the other ammo shoots, eh, OK. I would’ve expected some of the other factory ammo to shoot wonderfully as well.

    Now, I will say that the 65 barrel from them that I have did need to be shot a little bit before it got where I wanted it to be. What I mean by that, is that the velocity increased as the barrel broke in… which was a bit of a surprise to me because when I borescope it, it didn’t appear to be any different than it was before, and it didn’t have any extra buildup or anything along those lines.

    Jury is still out on this barrel, but I’m probably gonna load a bunch of 107 Sierra match Kings and call it a day.
     
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    #14
    jbell said:
    My initial thought is you have a sensitive barrel. Not saying it’s “bad”, but it’s not a “good” barrel. I have had a few over the years that would shoot well within the acceptable range (yes I am very picky), but we’re not exactly anything to brag about. These barrels required a very specific load, normally I was never able to get the expected velocity for the caliber / bullet / barrel specs and the accuracy. If I remember correctly I had to come off my “normal velocity range” around 100fps or more to get the expected accuracy...

    I am interested to know what comes of this. I hope all is well with you and yours my friend - Jesse
    Click to expand...

    I have the same as this, but with two barrels (a Bartlein and Krieger) at the moment. They definitely prefer to be run slower, and you get the accuracy that you'd hope for (sub-1/2 MOA consistently). Run them close to max published, and they'll turn into 1.25+ MOA slingers with every bullet and powder that I've got...and I've got a lot).

    I had one barrel a few years ago that was just the opposite. If you didn't mind cratering primers and ejector marks it was a laser. Run it at acceptable pressures with no signs and the groups doubled in size...seating depth, bullet, powder regardless.
     
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    #15
    GBMaryland said:
    You know, Herr Bell, I think you were probably right about this barrel. It’s a PVA osprey, and it is really interesting that the 107 grain federal gold medal match shoots fantastic, but some of the other ammo shoots, eh, OK. I would’ve expected some of the other factory ammo to shoot wonderfully as well.

    Now, I will say that the 65 barrel from them that I have did need to be shot a little bit before it got where I wanted it to be. What I mean by that, is that the velocity increased as the barrel broke in… which was a bit of a surprise to me because when I borescope it, it didn’t appear to be any different than it was before, and it didn’t have any extra buildup or anything along those lines.

    Jury is still out on this barrel, but I’m probably gonna load a bunch of 107 Sierra match Kings and call it a day.
    Click to expand...

    I fell in love with 110 smk and 112 Barnes in one 6creed barrel, both shot phenomenal(handloads). In a moment of weakness I sold that barreled action, but I kept all the bullets for my other 243/6creeds. I had a 7tw bart 243 spun up for an AI, and I started with the 110 and 112. I've owned several 243 and 243ai over the years and have a pretty good idea on accuracy and loads, generally finding a bughole load inside 40ish rds(with a good barrel). I spent 100rds of load work trying to tune and get good, consistent accuracy with either one of those bullets.....nada. 1 day I was bitching to 260shooter about the barrel and he said "how'd it shoot the 107smk?" I'd never tried them cause I was chasing the ultra high bc form factor bullets.....So I went out with 4 powder charges, 5rds each, with 107smk, and proceeded to agg a .368" 4x5 target. Sometimes it's best to let the barrel decide what it likes, not try to force it to like something. I find that forced loads tend to be more finicky to small changes in enviros and throat and component lot changes.
     
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