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Post by ET on May 6, 2022 6:12:28 GMT -5
A target can sometimes reveal what is happening to a load. I shot this target in the past and wondered what transpired to shift my group upwards. Here 6-shots were fired with 4759 and Harvester sabot using a standard Savage BP using 250gr SST bullets. Wait time between shots was about 15-min. The shots are numbered to follow their progress. Also started out with a cleaned 10ML-II. So, what does the reader feel is happening to cause this group elevation to shift?  |
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Post by dannoboone on May 6, 2022 11:30:11 GMT -5
No mention of bore brushing between shots, so I'm guessing
carbon buildup leading to higher pressure which would cause
faster bullet speeds and higher POI with each successive
shot. Again, just guessing.
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Post by mrbuck on May 6, 2022 13:07:19 GMT -5
Many times with centerfire rifles I have found the point of impact is lower when speed is increased . And many times when shot over a chronograph , with very carefully assembled handloads ,the first shot is the highest . The group took about an hour to shoot so the light on the target may have changed as well as the outside temperature . Since I just shoot three shots for an accuracy test , the first three look to be a triangular group of just about an inch . For a basic Savage ML that would be fine for me .
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Post by billc on May 6, 2022 13:17:28 GMT -5
I would see this with my Savage. If I started with a clean breech plug, my groups would string vertically for about 6 shots until the plug had "carboned" up. I believe it was the BP as I swab the bore with a wet acetone soaked patch and 2 dry patches every other shot. So I agree with Danno's assessment.
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Post by ET on May 6, 2022 20:28:13 GMT -5
Boy you gentlemen figured this out quickly. Yes, bore fouling influenced this group’s elevation shift. Once I started dry swabbing and some intermittent dry bore brushing this elevation shift went away. I didn’t realize how dirty a burning powder 4759 was until I saw the swabs. At this point in time with my learning curve the lesson for me was not to easily rule out bore fouling.
In case anyone is interested my computer shows this target was shot Oct-2011 which would be just before Nov. deer hunting season.
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Post by mrbuck on May 9, 2022 8:37:35 GMT -5
Interesting . Some MLII shooters feel the guns shoot better " dirty " or fouled . I prefer to start my shooting with a clean , dry barrel and run a dry patch every couple of shots . Will have to try adding dry brushing in the regimen .
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Post by ET on May 9, 2022 10:33:28 GMT -5
MrBuck
I incorporated brushing because of the crevices in a Savage bore that can hold fouling. 4759 is dirty enough IMO that dry swabbing and then bore brushing after 3-4 shots helps. Once I get through 4759 and use another powder, I will probably go your route of swabbing every second or third shot depending what dry swabbing reveals. Like you I prefer working with a clean bore results.
What I found interesting was your comment of a higher velocity load that hits lower on the target as I also experience this. I assume this is because faster shots spend less time in the bore so less affected by recoil motion.
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Post by ET on May 10, 2022 7:52:12 GMT -5
I thought I would display one more older target. All I'm going to say about this one is that the higher flyer was not always the last shot as this happened a few times before I caught on. So what do you think caused it?  |
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Post by ET on May 11, 2022 6:24:08 GMT -5
Okay one more clue. Interference with recoil motion.
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Post by dannoboone on May 11, 2022 15:52:56 GMT -5
Also happens during a "flinching" motion.  |
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Post by ET on May 12, 2022 5:46:41 GMT -5
I'm surprised no caught onto the last clue. Anyway the cause of some odd flyers was the result of what I call Sling Stud Bumping. If I wasn't careful of positioning my SML stock on the forward part of my homemade rest and made sure my sling stud was far enough spaced from my rest I would get the odd high flyer.
Mystery solved, chuckle.
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Post by dannoboone on May 12, 2022 11:50:00 GMT -5
Although it didn't seem to effect groups, that darned sling
stud tore up the stitching in my leather sand-filled front
rest pad. Since it didn't get used anyway, the sling stud
became history.
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Post by billc on May 13, 2022 17:50:22 GMT -5
Although it didn't seem to effect groups, that darned sling stud tore up the stitching in my leather sand-filled front rest pad. Since it didn't get used anyway, the sling stud became history. I've messed up a couple of bags because of the sling stud too! |
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