Sudden accuracy issues... copper fouling?
11-21-2009, 07:21 PM
#1
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
Posts: 3,802
Sudden accuracy issues... copper fouling?
Took my Rem 700 (257 Wby, 26", 1:10" twist OEM bbl) to the range today to shoot a load workup with a new powder and a couple bullets.
I had loaded both 110 grain Accubond and 115 grain Ballistic Tip (coyote exploder) bullets, using Hodgdon Retumbo powder. The workup was from 65.0 grains to 70.0 grains in 1/2 grain increments using Federal 215 primers. Bullets were seated to a COL of 3.17" (the recommended seating depth and SAMMI Max COL). At 70.0 grains there were no pressure signs at all.
Accuracy was atrocious. The best "group" was 3 of 5 shots into about 1.5" at 100 yards... the other 2 rounds from the group were way out of the group by almost 4". I did notice some tendency toward vertical stringing, but many of the flyers were just randomly all over the paper, with the "groups" being 6-8" at 100 yards. The only good news was than all shots landed on the 8.5x11" target, some just barely. The really strange thing is that this same rifle had been shooting 1/2 MOA groups the last time out with a different load (the powder for which I can't get because everyone's out of stock).
The prior load was with Barnes T-TSX bullets (which shot sub-MOA with the best groups sub 1/2 MOA), so I decided on a hunch to try some copper solvent (Shooters Choice) when I go home, and I'm getting what seems to be a LOT of copper out. I send a patch wetted with SC copper remover through, wait 5 minutes, and then dry patch until no more blue comes out. I've repeated this process at least 10 time (I've lost count), and I'm still getting some blue on the patches. Not nearly as much as the first few times, but it's still a noticeable amount. I'm wondering if this could possibly be the culprit behind the bad accuracy, or if I should be looking for other stuff, too. The temps were a lot cooler than the last time I shot it, and I waited at least a minute between shots and roughly 5 minutes between groups. My rule of thumb is that if I can't hold my fingers on the barrel just ahead of the chamber area for a 10 count, then the barrel is too hot to shoot.
I'm getting tempted to take the JB Bore Compound to the bore and lap it down to bare stainless and start over, but I don't want to mess up this barrel. I'm also wondering if it might be a bedding/pressure point issue, since the laminate wood stock has the typical Remington factory fore end pressure point on the barrel.
Thanks for your input.
Mike
I had loaded both 110 grain Accubond and 115 grain Ballistic Tip (coyote exploder) bullets, using Hodgdon Retumbo powder. The workup was from 65.0 grains to 70.0 grains in 1/2 grain increments using Federal 215 primers. Bullets were seated to a COL of 3.17" (the recommended seating depth and SAMMI Max COL). At 70.0 grains there were no pressure signs at all.
Accuracy was atrocious. The best "group" was 3 of 5 shots into about 1.5" at 100 yards... the other 2 rounds from the group were way out of the group by almost 4". I did notice some tendency toward vertical stringing, but many of the flyers were just randomly all over the paper, with the "groups" being 6-8" at 100 yards. The only good news was than all shots landed on the 8.5x11" target, some just barely. The really strange thing is that this same rifle had been shooting 1/2 MOA groups the last time out with a different load (the powder for which I can't get because everyone's out of stock).
The prior load was with Barnes T-TSX bullets (which shot sub-MOA with the best groups sub 1/2 MOA), so I decided on a hunch to try some copper solvent (Shooters Choice) when I go home, and I'm getting what seems to be a LOT of copper out. I send a patch wetted with SC copper remover through, wait 5 minutes, and then dry patch until no more blue comes out. I've repeated this process at least 10 time (I've lost count), and I'm still getting some blue on the patches. Not nearly as much as the first few times, but it's still a noticeable amount. I'm wondering if this could possibly be the culprit behind the bad accuracy, or if I should be looking for other stuff, too. The temps were a lot cooler than the last time I shot it, and I waited at least a minute between shots and roughly 5 minutes between groups. My rule of thumb is that if I can't hold my fingers on the barrel just ahead of the chamber area for a 10 count, then the barrel is too hot to shoot.
I'm getting tempted to take the JB Bore Compound to the bore and lap it down to bare stainless and start over, but I don't want to mess up this barrel. I'm also wondering if it might be a bedding/pressure point issue, since the laminate wood stock has the typical Remington factory fore end pressure point on the barrel.
Thanks for your input.
Mike
11-21-2009, 07:44 PM
#4
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
Posts: 3,802
Double checked all the screws for the scope and the action screws and they are properly snugged down. The scope is a Zeiss Conquest 4.5-14x50mm in Burris Signature rings and bases. I pray it's not the scope, but there is no reason that there should be anything wrong with it. The rifle is about a year old and has about 150 shots through it. I think that I'm going to pillar and "glass" bed the stock (I'll probably use Devcon Plastic Steel) and float the barrel just because it really can't hurt I don't think.
The darn thing is giving me fits. The previous load was 100 grain Barnes Tipped TSX bullets, Fed 215 primers, and 71.0 grains IMR-7828.
Here's the load workup target:
The targets I shot today I didn't even bother to take off the cardboard backer, I just threw them away because they really didn't resemble anything I'd call groups anyway. I'd expect better accuracy from a Chinese SKS. I'm also wondering if maybe the Retumbo is too slow. It seemed to be a little dirty, and I'm wondering if I just need to take the pressure up a little more. 70.0 grains showed no pressure signs at all with the 115 grain bullets, and I've seen Retumbo data for 100 grainers up to 76.5 grains, so a couple more grains (slowly, of course), might not hurt. I'm just pretty frustrated right now.
Mike
The darn thing is giving me fits. The previous load was 100 grain Barnes Tipped TSX bullets, Fed 215 primers, and 71.0 grains IMR-7828.
Here's the load workup target:
The targets I shot today I didn't even bother to take off the cardboard backer, I just threw them away because they really didn't resemble anything I'd call groups anyway. I'd expect better accuracy from a Chinese SKS. I'm also wondering if maybe the Retumbo is too slow. It seemed to be a little dirty, and I'm wondering if I just need to take the pressure up a little more. 70.0 grains showed no pressure signs at all with the 115 grain bullets, and I've seen Retumbo data for 100 grainers up to 76.5 grains, so a couple more grains (slowly, of course), might not hurt. I'm just pretty frustrated right now.
Mike
11-21-2009, 09:05 PM
#6
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
Posts: 3,802
It's an LSS Limited Edition with a laminated wood stock:
And, yes, it is the windage rear base (yeah, I know... now). The rings are the Posi-Align rings. I have the rifle apart now. Took the scope out of the rings and the base screws are tight and not bottomed out.
One other thing that I noticed was that there was a lot of blackening around the necks and front of the shoulders, like the pressure wasn't high enough to expand the brass enough to get a tight seal before the bullet cleared the neck. The brass is fireformed to the chamber and only necksized, so this blackening only goes to the front of the shoulder, but not to the case body behind the shoulder.
I would think that RL-22 would be a little on the fast side for the heavies in a case as big as the 257 Wby. 70 grains of Retumbo doesn't even fill the cases up to the bottom of the body/shoulder junction (but it's close). I'm also wondering about plaing with seating depth. The mag well is long enough to accommodate the big 3.6"+ COAL cartridges, so the 257 Wby has plenty of room, and then there's the very obvious and generous freebore shared by all factory Wby chambers.
I like it so much better when the load just works. Too bad I can't get any 7828 locally. I think that I'll try running the Retumbo a little hotter and see what happens. Seems a waste to have such a big case just to shoot a 100 grain pill.
And, yes, it is the windage rear base (yeah, I know... now). The rings are the Posi-Align rings. I have the rifle apart now. Took the scope out of the rings and the base screws are tight and not bottomed out.
One other thing that I noticed was that there was a lot of blackening around the necks and front of the shoulders, like the pressure wasn't high enough to expand the brass enough to get a tight seal before the bullet cleared the neck. The brass is fireformed to the chamber and only necksized, so this blackening only goes to the front of the shoulder, but not to the case body behind the shoulder.
I would think that RL-22 would be a little on the fast side for the heavies in a case as big as the 257 Wby. 70 grains of Retumbo doesn't even fill the cases up to the bottom of the body/shoulder junction (but it's close). I'm also wondering about plaing with seating depth. The mag well is long enough to accommodate the big 3.6"+ COAL cartridges, so the 257 Wby has plenty of room, and then there's the very obvious and generous freebore shared by all factory Wby chambers.
I like it so much better when the load just works. Too bad I can't get any 7828 locally. I think that I'll try running the Retumbo a little hotter and see what happens. Seems a waste to have such a big case just to shoot a 100 grain pill.
11-22-2009, 07:36 AM
#7
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
Posts: 3,802
Did a check to see what seating depth I'd need to touch the lands with the 110 grain Accubond. The short answer is that it's not possible to reach the lands with the bullet in the case. So I think that I'll load another work-up with the bullets seated 1 caliber into the neck and see what happens (which is a COAL of 3.35").
Mike
Mike
11-22-2009, 09:37 AM
#8
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
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I don't think that I'm ready to resort to moly. Once you go down that road, there's no turning back. If it turns out that the tsx/7828 load is all it'll shoot well, then I'll burn the barrel out using that load. I'd just like to find a good load with a cheaper bullet so I can afford to shoot the thing more that just when I'm hunting with it.
Mike
Mike
11-22-2009, 10:05 AM
#9
Nontypical Buck
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Join Date: Feb 2003
Location: Coralville, IA. USA
Posts: 3,802
You can't argue with results. 71 grains of IMR-7828 with the 100 grain TTSX produced a .4" group during the load workup. I posted the picture.
Last night I lapped the bore with JB and got the copper out. I'm going to load up another batch of ammo, seating at 3.350" and working up to 74 grains Retumbo. I've read of others having excellent results with Retumbo, and Nosler bullets have always been reliably accurate in every other rifle I've shot them through (which is almost all of them). I took the gun apart last night as well, including removing the scope to check all the screws. Put everything back together carefully and we'll see. One step at a time.
Time to go load some ammo.
Mike
Last night I lapped the bore with JB and got the copper out. I'm going to load up another batch of ammo, seating at 3.350" and working up to 74 grains Retumbo. I've read of others having excellent results with Retumbo, and Nosler bullets have always been reliably accurate in every other rifle I've shot them through (which is almost all of them). I took the gun apart last night as well, including removing the scope to check all the screws. Put everything back together carefully and we'll see. One step at a time.
Time to go load some ammo.
Mike
11-22-2009, 06:48 PM
#10
Fork Horn
Join Date: Feb 2003
Posts: 259
Mike,
I have had results similar to yours with Weatherby factory ammo. I bought a bunch of the 100gr Hornady factory loads because I couldn't find brass when I first got my rifle. After initial barrel break-in and getting it sighted in I was getting sub .75" groups. I was at the range with a buddy one afternoon and put about a box and a half thru it without cleaning - I know not a good idea - and my groups kept getting worse and worse, to the point I wouldn't even call them groups. I cleaned the rifle at the range and the results didn't get any better, needless to say I was getting very frustrated. When I cleaned at the range the solvent I used was just a powder solvent, did not remove copper. When I got home that night I broke out the Sweet's 7.62 and gave the barrel a thorough cleaning. Similar to your experience it took multiple rounds of a solvent soaked patch followed by dry patching before the blue patches quit coming. The next time I went to the range I was right back to the sub .75" groups.
I have not reloaded anything for my rifle yet. I had a pronghorn hunt coming up and not enough time to devote to load development, so I decided to stick with the factory stuff.
I was thinking all kinds of terrible things had gone wrong with my rifle before going back to the range and discovering that it would indeed shoot, and that the copper fouling had been the culprit. Given my results, and now yours, I have a sneaking suspicion that Remington had a group of barrels chambered for the .257 Wby that might be a little rough and very prone to fouling.
I think if I were you I would make another trip to the range and see how it shoots post scrubbing before I did anything radical.
I have had results similar to yours with Weatherby factory ammo. I bought a bunch of the 100gr Hornady factory loads because I couldn't find brass when I first got my rifle. After initial barrel break-in and getting it sighted in I was getting sub .75" groups. I was at the range with a buddy one afternoon and put about a box and a half thru it without cleaning - I know not a good idea - and my groups kept getting worse and worse, to the point I wouldn't even call them groups. I cleaned the rifle at the range and the results didn't get any better, needless to say I was getting very frustrated. When I cleaned at the range the solvent I used was just a powder solvent, did not remove copper. When I got home that night I broke out the Sweet's 7.62 and gave the barrel a thorough cleaning. Similar to your experience it took multiple rounds of a solvent soaked patch followed by dry patching before the blue patches quit coming. The next time I went to the range I was right back to the sub .75" groups.
I have not reloaded anything for my rifle yet. I had a pronghorn hunt coming up and not enough time to devote to load development, so I decided to stick with the factory stuff.
I was thinking all kinds of terrible things had gone wrong with my rifle before going back to the range and discovering that it would indeed shoot, and that the copper fouling had been the culprit. Given my results, and now yours, I have a sneaking suspicion that Remington had a group of barrels chambered for the .257 Wby that might be a little rough and very prone to fouling.
I think if I were you I would make another trip to the range and see how it shoots post scrubbing before I did anything radical.