Dirty barrel for F-Class?

D

DoubleGobble00

Guest
I am shooting a 6br using RE15 in a kreiger 30 inch barrel. My first F-Class match I started with a clean barrel. During the first 5 shots I had to adjust my elevation about 1 MOA lower. As the day progressed, I continued to dial my scope lower as I needed less MOA to reach the 600 yard target. After the match, I left my scope along.

I shot the next match this weekend and started with a clean barrel. My first shot was about 1.5-2 MOA low and about 2 MOA right. The windage MOA can be explained from dialing into the wind last time.. the elevation I assume is because the barrel is clean and the velocity is lower. I then adjusted the elevation about 2 MOA. After 5 shots I had to dial the elevation down 1/2 MOA and continued to dial the elevation down during the day. This caused me to drop several points during the first 10 shots.. The last 10 shots I only dropped 1 point.

Next match I want to avoid this... Should I leave my barrel dirty till next match (got about 100 round through it)... Or should I clean it and shoot about 20 rounds somewhere before the match to dirty it up? What do you do with your F-Class guns? Will it hurt the barrel to leave it dirty?

Thanks for the help.. I want to get the vertical adjustments out of the equation so I can concentrate on the windage.

DoubleG
 
Double G,

I think you'll quickly run into trouble if you shoot your 6 BR more than 90-100 rounds before cleaning.

I shoot a 6BR also but with Varget and get elevation change as you do but less than you report. First match of the day from a clean barrel I get 1 to 1-1/4 moa rise (diminishing with each succesive shot) for the first 5 of the unlimited sighter shots. I don't get much change in vertical after that that can't be blamed on changing conditions external to the rifle (it usually gets hotter during the day and shots will hit higher later in the day for that reason for instance). In succesive matches I assume that the first sighter on a dirty but cold barrel will be about 1/2 moa low and evaluate it as such. I trust the second sighter on a dirty barrel for windage and elevation.

Because this pattern is so repeatable (I find the same pattern in Palma and long range BR) I don't change my scope from my basic no wind elevation setting until I have enough sighter rounds to trust that they are settling in to the group. Lately I've been shooting the same 6BR in F-Class and 600 yd BR. For F-Class I clean at the end of the day, which means 90 to 95 shots. For 600 yd BR I usually clean between matches (forty or less shots) but sometimes after two targets (20 shots). I can't tell any difference on target other than the neccesity of a couple extra sighters required to get the barrel ready for record rounds after cleaning during a match. At this point in the life of this barrel (It had about 1800 rounds of 6-250 imp at 30" before being cut back to 27" and rechambered in 6BR for another 700 or so to date) going almost 100 F-Class rounds before cleaning hasn't seemed to hurt its accuracy when it returns to BR duty.

My suggestion would be to leave the elevation on your scope alone between matches (or maybe click down 1 moa from the end of your last match day's setting) until you have enough Match One unlimited sighter shots to trust that elevation trajectory is pretty much done drifting up. You might also try Varget to see if it settles down quicker for you as it seems to for me. If you continue to use RL15 and it takes 20 rounds to get the gun ready for record rounds then that's what you should do. In any event, after the initial trajectory change from a clean barrel, ongoing elevation increases should be incremental and not suddenly significant. As you see elevation changing on into the shooting day, chase it 1/8 or 1/4 moa at a time. If elevation changes 1 moa between shots during record fire I'll bet its from a head or tail wind push or let-up, not bore fouling condition change.

Greg
 
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Shoot two rounds

After I clean my barrel I try to shoot two rounds before I shoot a match. NOT the two sighters you are given, but two before that.
 
Greg and Chip - Thanks for the reply and the information. At first, I was thinking the barrel being dirty was causing it to climb through the day... But now I believe the barrel settled down after about 8-10 shots. I think I over compensated for the MOA after my first two shots. I think that go me confused and chasing my MOA.

This last match we had 5 sighters on the first string and 2 on the second string. The match before that we had unlimited sighters and I took 10 sighters before I started to shoot for score. My score that match was much better.


As the day progressed I only dialed 1/8 MOA about 3 times. It continued to climb but at small increments. The weather change from 45 degrees to 70 degrees was most likely the culprit like you mentioned.

Next time, I will be sure to shoot about 10-12 round before I go to the match. That should get me back on track.

Btw, just out of curiousity... Does it hurt the barrel to leave it dirty? Will the powder residue eat away at the barrel?

Thanks again,

DoubleG
 
Btw, just out of curiousity... Does it hurt the barrel to leave it dirty? Will the powder residue eat away at the barrel?
Click to expand...

I sure hope not... most of the F/TR shooters I know will go an entire long weekend match (250-300+ rds) without cleaning.
 
I don't think it could possibly hurt it that fast. I was thinking if you left it dirty for a month would it hurt it... Or how long would it take to damage the barrel.. if it does damage it at all....

DoubleG
 
DoubleG,

I think you're in the groove now. I don't think it "hurts" a barrel to leave it dirty (if stored in a benign environment) but it sure is easier to get one clean while it's still warm. That way you're not temted to shoot it "one more time" which can lead to unresolvable issues.

Greg
 
Thanks Greg.. I appreciate the help..

By unresolvable issues... do you mean the barrel will get too dirty and loose accuracy?

DoubleG
 
Yes. A barrel that is not cleaned will accumulate layers of powder and copper until accuracy is not recoverable.

Different cartridges foul at different rates due to variables including expanion ratio, powder speed and type, bullet velocity and bearing surface length and on. Monte mentioned that some F-TR shooters will go as far as 2-300 rounds with their 308s. That would toast a 6.5-284. By the same token some (very successful) Palma shooters will clean their 308s as rigorously as the br crowd.

I don't know if the fouling eventually gets so hard that it can't be removed by any means or the bullet running over the accumulation peens it into the surface of the bore but the accurate life of a barrel can be ended very prematurely by lack of cleaning even in score games that are less demanding of absolute precision than BR. I can't give you a round count for your 6BR that is the limit before you get unrecoverable accuracy loss. Its a ramp and not a cliff. But in general that point would vary inversely with the intensity of the cartridge as loaded in that application. I come from a BR culture and clean my LR score rifles more often than many.

This isn't specific but I hope it give you sense of how to approach your cleaning. It's popular to say your rifle will tell you when it needs to be cleaned but by then you might not get it all back.

Greg
 
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