Rapidly expanding groups?

[vividus1]

Hey all, I have an X-Bolt 26 Nosler that has about 50 rounds through it. Followed a basic break in procedure and shooting Double Tap ammo. Two bullets; Barnes LRX and Nosler Accubond. My issue is that the first group from a clean barrel is 1/2"-3/4", the second group is 2-3", then they all become basically flyers...group opens to 6-8" after only 6 shots. I am allowing plenty of time for the barrel to cool between each shot (typically 3-5 minutes). Same symptom for either bullet though the Barnes shoot the better clean barrel groups.

Surely it's not just copper fouling causing the rapidly expanding groups, right? Each time I clean the bore and shoot, the same thing happens. Anybody have ideas? Should I send the gun back for warranty? Thanks for any help or ideas y'all can provide!

 

[WeiserBucks]

Could it be that you have a very rough bore that is fouling very quickly? Is it difficult to clean?

 

[Creedmoor shooter]

My x-bolt in 7mm mag kinda did that..... it was shooting .75 in groups then went to like 2.5-3in. I scrubbed the crap out of that barrel and problem solved. Not sure that's your issue here. Let me clarify, it only shoots well on a clean barrel or only your first group of the day?

 

[ATH]

My Sendero did that, just not QUITE so quickly. I could get about 20 accurate rounds. I did a Tubbs treatment skipping the most coarse bullets and it was greatly improved.

 

[Schnyd112]

Does it settle down after you shoot 20 or so, without cleaning? same theory as above, but in some cases the copper will stop peeling off the bullets, fill the rough spots in the barrel, and shoot fairly well after equalized.

My .220 swift took 20+ rounds after stripping copper to settle back into .75-1 inch groups at 100. I stopped cleaning it unless things got ugly. Usually between 300-400 rounds i would need to clean, strip copper, and start over. I eventually replaced the barrel and that solved all my problems.

 

[vividus1]

Could it be that you have a very rough bore that is fouling very quickly? Is it difficult to clean?

It seems to attract copper fouling much heavier in the first few inches inside the muzzle and less down near the throat. Does that make any sense?

 

[vividus1]

Does it settle down after you shoot 20 or so, without cleaning? same theory as above, but in some cases the copper will stop peeling off the bullets, fill the rough spots in the barrel, and shoot fairly well after equalized.

My .220 swift took 20+ rounds after stripping copper to settle back into .75-1 inch groups at 100. I stopped cleaning it unless things got ugly. Usually between 300-400 rounds i would need to clean, strip copper, and start over. I eventually replaced the barrel and that solved all my problems.

Haven't shot more than 12 rounds without clearing copper. The gun only has about 50 rounds through it. By the 12th round, it's flinging so bad I can't bear to keep wasting ammo.

 

[vividus1]

My x-bolt in 7mm mag kinda did that..... it was shooting .75 in groups then went to like 2.5-3in. I scrubbed the crap out of that barrel and problem solved. Not sure that's your issue here. Let me clarify, it only shoots well on a clean barrel or only your first group of the day?

Only on a clean barrel, and it doesn't even want a fouling round...the first 3 rounds shoot awesome.

 

[Schnyd112]

Haven't shot more than 12 rounds without clearing copper. The gun only has about 50 rounds through it. By the 12th round, it's flinging so bad I can't bear to keep wasting ammo.

I know it isn't cheap shooting that caliber, but my advice would be a new barrel if you can't find a solution. A box of ammo used to experiment is far cheaper than scrapping a barrel.

Have you chrono'd anything to know where your velocities are? I don't have much experience with copper bullets but maybe they are just going too fast.

 

[coop2564]

I would call browning. My Xbolt never fouled like this. I can shoot 100 rds and its still grouping very well. are you sure you are getting all copper out from first break in? Copper is very hard to gt out and can take days with some solvents. I have a Sako that fouls and starts flying them everywhere but it takes about 50 rds, groups about 1" until 50 or so. But its very hard to clean out copper from it. Using benchrest copper solvent it takes about 3 days of soaking and scrubbing every 3-4 hours to get it all out.

 

[Joefrazell]

It seems to attract copper fouling much heavier in the first few inches inside the muzzle and less down near the throat. Does that make any sense?

More velocity near the end so yeah it makes since and I've noticed it in my rifles as well

 

[Creedmoor shooter]

As said before I'd make sure your getting it all.... what solvents are you using?

 

[Joefrazell]

I've never seen copper fouling cause this. I'd send it in to browning as this is definitely not normal. You should be able to get better then 6" with that gun even with fouling. Usually when a gun opens up from fouling it goes from .75" to 1.5-2" not 6-8".

 

[vividus1]

I know it isn't cheap shooting that caliber, but my advice would be a new barrel if you can't find a solution. A box of ammo used to experiment is far cheaper than scrapping a barrel.

Have you chrono'd anything to know where your velocities are? I don't have much experience with copper bullets but maybe they are just going too fast.

We chrono'd it the first day...3590-3615 was the range over 9 shots with the 127 Barnes LRX.