Dirty barrel experiments.



  • So I'm doing some experiments with barrels. First up is my 6BR. I'm tracking accuracy/precision through a dirty barrel.

    This rifle has proven to be a 1/3moa or so rifle in the past on clean barrel. I'm going to refuse to clean it... I'm just going to keep shooting and shooting it.

    Here's some shots from today at 336rnds. 5-shot groups @ 100yds.

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  • You don't happen to have a picture of one of the groups clean? I'm sure you do, it would just be nice to have a visual before and after.



  • I posted these in a different thread the other day... this was after I cleaned it. As I mentioned the bottom/right one was my son tripping over my feet. So its right around the same. Potentially marginally better when clean. Tight little cluster vs these which are strung out a bit.

    jj2bJQMh.jpg

    I can tell you right now, if I can maintain this kind of performance without ever having to clean... I'm pretty sure I can live with that on certain rifles. This barrel never shot in the .0's or .1's anyway. My main concern is regarding zero drift and/or FPS drift. That's what I hope to find out via this experiment.

    Around 200rnds this rifle pressures up bad and jumps up about 100fps, so I backed off that 30gr load down to 29gr, and that's the groups in the previous post.



  • I'd also be curious to see if ES jumps up.



  • I'm going to include some chrono work as well as distance shooting throughout to try and learn as much as possible. Though if dope tracks at distance, and rounds stay tight on target up close as well as far away... that will pretty much tell everything that a guy needs to know.



  • The idea behind this thread reminds me of the argument of changing your oil every 3,000 miles vs the cost of just replacing the engine after so long from not changing the oil.

    Looking forward to seeing the results.



  • Went and checked some load dev. 29gr was a little toward the high side of the node me thinks. 28.4 (dot 3) was awfully impressive, as was 28.6 (dot4). So I loaded up at 28.5 and proofed.

    3m6AIfwh.jpg

    Sure enough, it's impressive alright.

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    See how its shooting? Note the group size and location.

    So I attached the magnetospeed.

    PBsmvXWh.jpg

    Remember that tool on an other forum talking about how magnetospeed doesn't affect group size... just POI? Well I went from one hole to a 1moa group simply by attaching it. So yeah... myth busted? Prolly. Now if only tools would stop perpetuating myths on forums.

    iQZLWuHh.jpg

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    SD of 2.6? Yeah, good enough. I put 3rnds on a quarter down at 300yds too... but too lazy to walk down and take a picture.

    So, suffice it to say despite being dirty, the rifle shoots. 387rnds since last cleaning and it's shooting quite well. I shot a few more dots and called it good for the day.



  • @orkan
    Interesting tread. I've never documented any results or done in actual "test" either, but my experience has been Barrel dependent. With the current barrel on my 6.5x47 I've not seen any lost in accuracy to over 400 rounds 5 rounds usually in the .250 to .275 range, but the previous barrel would turn to a shotgun type group in under 200. The current barrel is a Bartlien 5r and the other one was a Krieger. The Krieger shot about the same mid .2's "which is about all I can do" until around 180 or so then it went to like 1.5 moa. It didn't stay with me long. I have a ruger precision in .223 that so far has been doing really good for a factory barrel. It has 477 rounds down the tube and hasn't been cleaned in roughly 250 rounds with no negative affects on accuracy. I'm curious to see your finial results



  • Shot this yesterday. Now 426rnds since cleaned.

    6k89Gi7h.jpg



  • I'm feeling very good today. Got the rifle tracking flawlessly. Really just one of those days where it doesn't matter what rifle I grab, I can just make it work for me.

    5 shots on the left, 3 on the right. Spent the first two zeroing... otherwise that's the first 10 of the day. 436rnds on the barrel now since it's been cleaned. 1356rnds total.

    rFq5zx2h.jpg



  • It seems that this "don't clean your barrel" theory has a couple main requirements so far.

    The first is that the barrel be broken in normally. As in, you can't just not clean it when it's new, and you must clean it good for the first couple hundred rounds. It needs to get past its cranky teenage rounds.

    The second is that you must wait until after that, and after it has reached the round count where it would normally scatter and pressure up before you do load dev. In other words, the barrel must be broken in and then completely fouled before load dev can be done. This would seem to take no less than 300rnds of barrel life, and possibly more. This would seem to be a pretty big consideration if you've got something that will torch barrels quick. If you can come onto a load that shoots reasonably well early on, it won't be much of a big deal. However if you stumble early, then waiting for the dirty bore condition to exist might just use up a considerable portion of barrel life. Obviously this is not the case with 6BR's, Dashers, or other small 6mm's that have barrel life well past 2000rnds. Though I'm very curious how this method would shake out on a more overbore cartridge like a 6CM or 22CM.

    A friend of mine and local shooter turned me on to this whole thing. I'm having a fun time trying to proof it. :)



  • @orkan said:

    I posted these in a different thread the other day... this was after I cleaned it. As I mentioned the bottom/right one was my son tripping over my feet. So its right around the same. Potentially marginally better when clean. Tight little cluster vs these which are strung out a bit.

    jj2bJQMh.jpg

    Around 200rnds this rifle pressures up bad and jumps up about 100fps, so I backed off that 30gr load down to 29gr, and that's the groups in the previous post.

    Is that jump of 100fps common with other rifles with similar size/weight bullets?



  • Yes, most rifles will experience a FPS bump and a propensity to show pressure when they get fouled.



  • If one were to load to the bottom end of a node when the barrel was clean...would it be possible to shoot through the velocity increase without changing the load?



  • @dddoo7 said:

    If one were to load to the bottom end of a node when the barrel was clean...would it be possible to shoot through the velocity increase without changing the load?

    It's very possible. I'll happily assign that project to you and you can report in here! :)

    However I would think that where you would need to be would be farther away. Very hard to predict without data from previous workups to use as a delta. For instance, my node was at 30gr on a clean barrel. Yet I'm all the way down at 28.5 right now.



  • I'm happy cleaning every couple hundred right now. I am just feeling like I can call my shots. I don't want another variable yet.



  • Just want to make sure I understand what we're talking about here while I'm waiting for Irma. Once we bracket the range of powder loads and split the difference to get right in the middle of the node.(theoretically). I'm guessing this should be done on a relatively clean barrel. Then we Chrono the rounds to get out FPS. Then as the pressure rises due to barrel fouling, we have to reduce the charge to accommodate the 100 FPS increase in speed due to the fouling.

    Did I get this right. Just when I think I've got some aspects of reloading figured. Round count since last cleaning has to get into the mix along with round count on the barrel.

    I'm wondering if there's a cleaning interval that keeps your bug holes without having to change your powder charge, or do you waste too many rounds refouling your barrel to get you where you want to be accuracy wise so the charge tweak is the to go to you get to the 200-300 round count and you reach an issue with accuracy that cannot be corrected by modifying the powder charge.



  • My 308 is consistent to about 200 rounds. This last time when I cleaned...I used wipe out patch out/accelerator. Then I dried the bore with several dry patches. I usually follow that up with a patch of kroil and another dry patch, but this time I intentionally left off the kroil.

    With a clean dry bore, the barrel shot bug holes.



  • @martino1 said:

    Just want to make sure I understand what we're talking about here while I'm waiting for Irma. Once we bracket the range of powder loads and split the difference to get right in the middle of the node.(theoretically). I'm guessing this should be done on a relatively clean barrel. Then we Chrono the rounds to get out FPS. Then as the pressure rises due to barrel fouling, we have to reduce the charge to accommodate the 100 FPS increase in speed due to the fouling.

    Did I get this right. Just when I think I've got some aspects of reloading figured. Round count since last cleaning has to get into the mix along with round count on the barrel.

    I'm wondering if there's a cleaning interval that keeps your bug holes without having to change your powder charge, or do you waste too many rounds refouling your barrel to get you where you want to be accuracy wise so the charge tweak is the to go to you get to the 200-300 round count and you reach an issue with accuracy that cannot be corrected by modifying the powder charge.

    Yes, obviously the way I've been doing it and recommending to poeple, works. The way I've been doing it is simply to clean the barrel every couple hundred rounds or whenever is necessary to preserve accuracy. Keeping a barrel log and tracking honest shots tells you exactly when this is. You only need 3-20rnds to foul back in after cleaning, and it will bug hole until it gets fouled. Yes, that works. However the quest for knowledge is eternal.

    This experiment is to determine if you can leave it fouled.

    So as I said, once the barrel is broke in and subsequently fouled, you'll reach a round count somewhere around 200-400 since last cleaned and it will likely speed up and pressure up due to the fouled/constricted bore. At this point, you do an entirely new load development session. This will show you where the "fouled" node is, and this is completely independent of velocity. Velocity is a result, nothing more.



  • @orkan

    I'll be very interested to see the results of this test. Especially the change in powder charge as the round count goes up.

    Tests like this really help advance the sport Orkan. Thanks for doing this and sharing your findings.



  • 506rnds since last cleaned and today I cleaned a KYL rack at 530yds with it. Smallest target is 2.5" on this rack. Wasn't on my first try... but my 3rd try I think. Had an 18-25mph wind today, so it was a little rough. Bottom line is the rifle is still shooting excellent.

    My 6.5LRM has upwards of 200rnds on it since last cleaned and I was absolutely smashing with it today. I first round hit a 1.5" target at 530yds, then a 6" target at 671, then a 4" target at 820, followed by a 12" target @ 658 and a 12" target at 985. I couldn't be reasoned with. ;)



  • @orkan

    Wow son that's some pretty spry shooting in wind. Have a whole new appreciation after I got humbled with 2-15mph variable wind. Was used to small variations of 5 mph. 13 kicked my bum. Need to get out in the variable stuff more and practice.



  • 516rnds since cleaned.

    3rnds, 4rnds, 3 rnds. Right > left gusts came up but I just held center dot. They were wiggling me around a bit too... so whatever. I could feel the groups could have been smaller but it is what it is.

    62Pr8xxl.jpg
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  • @orkan they could be better lol. Most shooters would be jumping up and down if they could put groups down like that. I know your not most shooters though.



  • Any new updates here



  • Sorry... 6br sits back of the bus when I'm slaying.

    3qHgMCNh.jpg



  • @orkan man yea good job, yal have some beautiful song dogs up there. In my neck of the woods the are smaller, skinny, and missing half their hair. I'd love to get into calling and hunting them, I mainly kill them at night while hog hunting



  • @orkan
    Thought you'd be running out of yotes to shoot by now.šŸ‘



  • That thing has more red in its coat than I've seen in FL and PA.



  • 578rnds since cleaned. 5 @ 100yds.

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  • I had @brittel time me on a dot drill. I pushed a little too fast. Missed a few breath cycles. 612rnds since cleaned now.

    1 minute 12 seconds.

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    Only 12 hits.

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  • Hey Greg,

    Loving this experiment and info. So, if Iā€™m understanding at this point, it appears once you get to your normal cleaning point (where accuracy degrades), you grind through that and do a new load dev. The reason accuracy degrades is do to pressure increasing your velocity and pushing out of your node. Is this understanding accurate?



  • @pizfiz Yup, that's pretty much in line with what I'm thinking.


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