Interesting group results, lots of questions

GBMaryland · Oct 28, 2024

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:

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…):

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

D̷e̷v̷i̷l̷D̷o̷c̷A̷Z̷ · Oct 28, 2024

The only real difference is the can?

I think you have your answer.

jetjock07 · Oct 28, 2024

Thunderbeast for the win!!!!

D̷e̷v̷i̷l̷D̷o̷c̷A̷Z̷ · Oct 28, 2024

Shoot the rifle without any muzzle device or can if you think it’s the barrel.

As you start bolting things on see where it takes you.

This isnt rocket surgery

Baron23 · Oct 28, 2024

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

I'm betting the can. Go shoot it with the U9 cold bore and see what results you get.

hafejd30 · Oct 28, 2024

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

GBMaryland · Oct 28, 2024

I will give it a try tomorrow with a cold gun and the ultra9…

Let me see if I have any of that 112 left!

I’ll report back the results

whatsupdoc · Oct 28, 2024

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.

Tikkaguy · Oct 30, 2024

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.

GBMaryland · Oct 30, 2024

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.

diggler1833 · Oct 30, 2024

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.

jbell · Oct 30, 2024

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

GBMaryland · Oct 31, 2024

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.

diggler1833 · Nov 1, 2024

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

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.

6brshooter · Nov 1, 2024

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.

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.

D_Lamz · Nov 1, 2024

My PVA osprey barrel in 6cm loves the Barnes 112. My wallet does too haha

GBMaryland · Nov 8, 2024

Heh.

So I started chasing the load for the OEM FGGM 107SMKs.... I've arrived at 38.1gr of H4350 in Peterson Brass with Federal Match LRPs...

I also decided to take a considerable look at the bore of the PVA M24 Osprey. There is certainly more copper about 1/3 of the way into the bore from the chamber end. I'm going to remove all of the copper and refoul the barrel. We'll see. Since bore scopes LIE... not sure how much I should care about the copper, but there is significantly more in this one zone of barrel (nothing for the first few inches outside of the chamber, nor in the last 2/3s-3/3s of the barrel).

Reached out to PVA and they are happy to check... as always, they are awesome. (May just order a carbon fiber osprey for giggles, but I want to work this one out first.) Not sure I'm going to waste their time if I can get 107s loving life in that barrel.

Of course, I was using a Hornady "match" seating die... and match my ass... it does not seat bullets perfectly concentric. (aka It's super sensitive to neck tension, where as the Reddings don't seem to have that issue. So I ordered the SAC bullet seater, and we'll see how that goes! $$$)

6brshooter · Nov 8, 2024

I've had just as good results with Hornady seater as I have with forster ultra, widden, and redding. I must be doing something wrong.

GBMaryland · Nov 8, 2024

I guess it’s possible but…. How exactly?

Baron23 · Nov 8, 2024

GBMaryland said:
I guess it’s possible but…. How exactly?

How did you measure bullet run out from the Hornady seating die? Or was is so bad it was just visible with naked eye (or a fully dressed eye for that matter haha)

GBMaryland · Nov 8, 2024

It’s actually obvious with the naked eye… the seating through the neck is not equal in 360° of the neck. In other words, the neck bulges on one side versus the other…. If it bulged equally in 360° then it would be seated properly, even though that’s a little odd.

So I suspect I have to adjust the neck tension… which typically I don’t have to worry about with most of my reloads.

I’ve ordered different mandrels for my resizer

ma smith · Nov 8, 2024

GBMaryland said:
It’s actually obvious with the naked eye… the seating through the neck is not equal in 360° of the neck. In other words, the neck bulges on one side versus the other…. If it bulged equally in 360° then it would be seated properly, even though that’s a little odd.

So I suspect I have to adjust the neck tension… which typically I don’t have to worry about with most of my reloads.

I’ve ordered different mandrels for my resizer

I'm not sure what your process is, but I found using pin-guages really helps keep track of neck tension. Even with good components and process steps, running a pin-guage into the case necks help keep everything honest.

GBMaryland · Nov 8, 2024

I certainly made the assumption that Peterson brass would come with the appropriate internal diameter size for the neck….

But yes, I’m gonna go downstairs and start measuring everything…. Probably end up buying the right pin gauges for 6 mm.

jbell · Nov 8, 2024

You can most certainly use a pin gauge, but if you have a ball micrometer just measure the neck wall thickness in 4 points to make sure the wall thickness is concentric. Mic bullet diameter and select the appropriate size bushing taking into consideration the 0.0005" spring back good brass (not work hardened) has. Also do not use an expander in the sizing die. This has been my method for a very long time with excellent results. I much prefer this method to the seat a bullet and measure the neck that some people recommend.

GBMaryland · Nov 14, 2024

Ok, as a follow-up:

I found that a section of the barrel tended to get more copper fouled that the rest of it. When I cleaned it out (by soaking it with Cu Remover from Boretech) it shot more consistently. At this point, I need to check the other bullet types and see if the groups are smaller now.

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Interesting group results, lots of questions

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