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Post by Richard on Oct 14, 2015 12:58:30 GMT -5
A great day to be at the range with Herman and Bill……………60* and clear with no wind. This first group is particularly noteworthy as I have been experiencing this cycle for a number of years now. Not every time but enough to lead me to believe there is something to it. It involves cold barrel velocities and grouping and a shift to a different POI when warming? If you follow my velocity readings and where the shots grouped you will see what I mean. Let me say this…………The hold in right on, the scope is 32X NF and the trigger is 2 oz. Shilen. It only fires when I “touch it!” Starting with the cold clean barrel: The first three shots averaged 2857 fps with a 16 fps ES. They grouped nicely in .510” ½” high and ½” right. The barrel is now starting to warm (not hot, just warm) Shots #4 now drops to 2828 fps……………..shot #5 comes out at 2832 fps and are in one hole but an inch higher?................I was now intending to fire a sixth shot to see if it also went into the same hole?.............But, we were interrupted by a flock of turkeys walking about 50 yards out in front of us!  host image online As we killed some 10 minutes, the barrel had a chance to cool back down to ambient temperature but I still decided to fire the 6th. shot. Note: the velocity went up to 2843 and impacted the top of the first three shot group. It left the second group at .339” which was also good. But, it seemed that the slight rise in velocity over shots 4 & 5 caused it to drop a little . Had this been the first time it happened, I would have just shrugged my shoulders and said: “Oh well?” But I have seen this very similar thing happen numerous times in the past…………Thoughts? If you look at the average velocity for all ten shots you will see it was 2861 with an ES of 58 fps. If you then eliminate the first cooler barrel shot (2895) the ES for the remaining nine shots is only 31 fps. Getting more used to using the “come ups” on the NF, I dialed up and using a similar load (10/60 vs. 10/59) , put two (1 & 2)shots on the steel gong at 300 yards. I then went to the bullseye and found my elevation almost right but the POI a little to the right. (shot #3). Adjusted the scope a little more left and put seven shots down range. Best five out of the seven in just under two inches. (made another scope adjustment) For the third group I switched to the 250 TEZ with the same 10/60 duplex. Not a one holer but five sub MOA is plenty deer good. Based on the low, 18 fps, ES, I would have thought the group would have been a little better? Maybe some slight wind picking up which I did not see………..Bill thought he was seeing some activity on the grass. Another scope adjustment………… The last group was shot with the same load as #3. Here, I had 10 fps ES for six shots. The best five out of six was 2.6”, much similar to group #3. And that is it! No earth shaking results, just what I found with my gun and loads on this date.  images hosting free upload |
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Post by Deleted on Oct 14, 2015 13:20:11 GMT -5
Another good outing and good reporting. I'd be hard pressed not to tag one of them birds.
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Post by schunter on Oct 14, 2015 14:03:42 GMT -5
Very nice report as always Rich. Good information to ponder.....
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Post by 12ptdroptine on Oct 14, 2015 15:18:50 GMT -5
As always a good read Richard. I always look forward to your range reports
Thank You
Drop
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Post by Deleted on Oct 15, 2015 9:06:11 GMT -5
So i'am assuming the heat is expanding your barrel diameter ,thus more volume in your barrel and more energy exerted into the obturation of the bullet to fill the barrel...Slowing your velocity enough to change poi induced by recoil lift from a longer exit time....Thanks for the data....
BUT ..there are other things going on since you start off with a clean barrel....You are getting fouling buildup which adds friction but also increases pressure capture....these might off set each other....A lot to think about...That's why I love this stuff..... |
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Post by Richard on Oct 15, 2015 19:54:32 GMT -5
That is why I am going to repeat the same test next week. Then double cool the barrel (put the cooling rod in until it is ambient------re cool it and re insert it to get the barrel actually cold) and re run the test. Now the barrel will already be fouled and see what happens. The thing is Allen, unless you shoot and test with a chronograph, you mill miss this stuff? At least with knowing the velocities, you have something to judge by. Otherwise you would scratch your head and say..............This load shoots vertical or this load is no good? When you know your scope is good, your rifle is accurate, your hold is good, your trigger is breaking without disturbing the gun......something is causing the group to shift and velocity to drop. Without the chronograph you just scratch your head! If, your only intention is to have a load to hit a deer or whatever at a give distance and your group size will do that, then you don't need the chronograph? If, on the other hand you want to Kyle's butt in the spring..............you better have the chronograph!  |
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Post by Deleted on Oct 15, 2015 22:52:19 GMT -5
Maybe the weight of the bullet is coming into play here also...not producing enough pressure on the load for the powder to burn at its full potential....? It seems to me ,the closer you approach 300gn the more consistent I see people shoot....
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Post by Hank on Oct 15, 2015 23:13:18 GMT -5
Lots of good shooting there Richard.... Now if you can talk the range masters into not feeding the turkeys on Tuesday maybe you could get a few more rounds down range...
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Post by Richard on Oct 16, 2015 13:29:11 GMT -5
That is what is nice about our club..........NO range masters! Being a private club We can do our own thing when we want. Actually Hank, the club does plant various food plots around the 175 acres and farms are all around the perimeters of our facility.
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Post by Hank on Oct 16, 2015 14:24:05 GMT -5
You do have a great place to shoot and the wildlife is just a bonus... Those turkeys know they are safe so they just keep on walking the range getting the easy food...
What does the Tom turkey say to the Jake turkey every Tuesday...?
Richard and Herman are shooting today., let's go get breakfast,, they can't hit us anyway...
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Post by doggzoe on Oct 18, 2015 19:47:22 GMT -5
Had 4 long beard between me and the 100yd target when I pulled up to the range Thursday evening. They just kept on feeding all the time I was setting up and didn't move out until I got to within 30yds while walking to put up a target. They just moved up the hill towards the trap range and kept on feeding. They get used to the noise and people moving around. Two years ago I had a small buck bedded across from the 100yd target about 20yds away just inside the timber and stayed there all time and was still there when I pulled my targets.
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