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Old 01-07-2013, 22:07   #1
Any Cal.
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Food for thought...

I checked my powder drops the other night, and found them .4g higher than I thought they were. Moral of the story being... doublecheck your powder drops.

After reducing my powder drops .6g, I chrono'd 10rd strings of each. Average velocity was 1fps different! Less powder, less recoil, and within 1fps-I'll take it. Moral of the story is...you may be surprised at the performance of a "lighter" load.

The lighter loads did have far higher velocity swings than the heavier ones, so am undecided as to which one I will use. The hotter loads had an es of 17 and an sd of 4, the lighter loads are about 42 and 15. Average stayed the same, accuracy appeared to be similar for the couple of groups that were checked. All was with standard rsa.

Bought powder at a place I haven't tried before, and saved $5/lb-almost 20%. Might be worth looking around if there is a new store in town. You could probably see similar savings by switching to a faster powder,i.e. quit using #9...:-)
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Old 01-09-2013, 00:08   #2
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Good thoughts AC. I weigh samples pretty regularly from my powder throw for that very reason.

That's funny that you mention using faster-burning powders. I have been playing a lot with lower velocity 10mm stuff lately. First Accurate no. 5. Works great for a 180 @ 1000 - 1050 fps. Recently I picked up a can of WSF to try. My 180 grain plinker load will use about 6.0 grains of powder vs. my 13.0 grain A9 loads! Thanks to Freakshow10mm for guidance there. The WSF load should approximate the "FBI Load." I know, I know. Not sexy in these parts.
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Old 01-09-2013, 07:38   #3
BMiracletx
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Dang, I shoot a lot of "reduced loads" in all my guns. My favorite reduced in 10mm is 155 plated bullet over 6.0 grs 231... chronos a tick over 1000 fps and drops the brass at my feet... but accurate as heck and the paper target is just as dead! (but I still shoot my 200 XTPs @ 1200 with Longshot... just not much except for when out hunting).
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Old 01-09-2013, 10:23   #4
Andrew Wiggin
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I usually try to go for either the smallest SD or as I work up a load, I look for that spot where the curve starts to get less steep. That is, if I'm getting about 40 fps with every 0.2 gr increase and then I see 20 fps increase, I'll stop just before that. Power is nice and all and if we didn't like power, we wouldn't shoot 10mm, but efficiency and accuracy are good too. When it comes to self defense and hunting, accuracy (shot placement) is more important than any other factor.
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Old 01-09-2013, 14:34   #5
Any Cal.
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Accuracy is good, but it really depends on the size and distance of the target, and should be balanced with shootability, reliability, and terminal ballistics,(if an issue).

I know a lot of people shoot reduced loads, but since it is about the same cost and effort to make them full-power, I guess I am too lazy to readjust the dies and powder measure...:-)
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Old 01-10-2013, 01:31   #6
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Quote:
Originally Posted by Any Cal. View Post
I checked my powder drops the other night, and found them .4g higher than I thought they were. Moral of the story being... doublecheck your powder drops.

After reducing my powder drops .6g, I chrono'd 10rd strings of each. Average velocity was 1fps different! Less powder, less recoil, and within 1fps-I'll take it. Moral of the story is...you may be surprised at the performance of a "lighter" load.

The lighter loads did have far higher velocity swings than the heavier ones, so am undecided as to which one I will use. The hotter loads had an es of 17 and an sd of 4, the lighter loads are about 42 and 15. Average stayed the same, accuracy appeared to be similar for the couple of groups that were checked. All was with standard rsa.

Bought powder at a place I haven't tried before, and saved $5/lb-almost 20%. Might be worth looking around if there is a new store in town. You could probably see similar savings by switching to a faster powder,i.e. quit using #9...:-)
Great point about velocity variation on reduced loads. I've found that most powders have a "sweet spot" for velocity consistency and standard deviations. Usually that sweet spot is towards the upper end of the max load number. I have seen this with both 800-X and Longshot loads in 10mm. Also have seen this with several rifle powders. Varget seems to love full cases and max loadings for velocity consistency. But there are a few powders that don't exhibit this behavior. Bullseye seems to run extremely low standard deviations in everything I've loaded it in (38Spl, 9mm, 40S&W), regardless of level of load. I'm not really sure why this is, but I've accepted it and load accordingly.

I would say though, that an extreme spread of 42fps in a pistol load is rather insignificant, unless you are trying to hit targets at 300yds and out. As long as the close range accuracy is good, I have no problem with such numbers.
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Old 01-11-2013, 03:25   #7
Any Cal.
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42 is fine, but it was a real letdown watching the #s swing on the chrono after watching the first set stack so close together...

I had reduced the charge weight so the stock barrel could be used with the loads as well, it will be interesting to see what the difference will be from losing 1/2" of barrel. Any guesses? I am thinking an average of 1080 in the stock barrel.

All this began w/ the thread on pressure... I had remarked that my loads would probably smile in the stock barrel, so was interested to see exactly how much velocity I gain for using what I assume are overpressure loads in a barrel 1/2" longer than stock. At this point it is obvious the extra pressure was not providing velocity, so the difference in barrel length is next. Is there really a point to taking the risk? Either an answer or more questions after the next chrono run.

Last edited by Any Cal.; 01-11-2013 at 03:37..
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Old 01-11-2013, 23:20   #8
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Originally Posted by Any Cal. View Post
42 is fine, but it was a real letdown watching the #s swing on the chrono after watching the first set stack so close together...

I had reduced the charge weight so the stock barrel could be used with the loads as well, it will be interesting to see what the difference will be from losing 1/2" of barrel. Any guesses? I am thinking an average of 1080 in the stock barrel.

All this began w/ the thread on pressure... I had remarked that my loads would probably smile in the stock barrel, so was interested to see exactly how much velocity I gain for using what I assume are overpressure loads in a barrel 1/2" longer than stock. At this point it is obvious the extra pressure was not providing velocity, so the difference in barrel length is next. Is there really a point to taking the risk? Either an answer or more questions after the next chrono run.
You didn't say what powder or bullet weight, but based on data that I have collected with a 6"LWD vs. the 4.6" stock G20 barrel, and then adjusting those numbers for 0.5" barrel length difference, I would say about a 35-50fps difference. With heavier bullets (180-200gr) it will be closer to 35 fps, with light bullets (135gr) it will be closer to 50 fps.

I did fail to mention on my previous post, that a low ES of velocity does give me more confidence that the load is going to be consistent pressure-wise, also. Wild velocity swings for a particular load tend to make me wonder about whether it's something I would want to load a lot of, or just move on to a different recipe that is better behaved.
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Last edited by TDC20; 01-11-2013 at 23:23..
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Old 01-12-2013, 01:44   #9
Any Cal.
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Pressure swings are what concern me at this moment, as I want the loads to perform in the stock barrel. With the wider swings it looks like I am getting a few that are higher velocity than heavier loadings... so conceivably some of those would be higher pressure as well. Will see what happens, hopefully tomorrow.

Good guess on the velocity, bullet is highly classified so I can't say anything about it... :-)
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Old 01-21-2013, 21:16   #10
Any Cal.
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Ok, was it Plato that said you can learn more in an hour of play than a lifetime of conversation? I have been playing...

Still haven't bought a batt for the chrono, but got some (slightly strange) readings. Using another box of reloads through the 5.3" bbl, I got 1154 avg for 4 shots. This is almost 20fps higher than usual, so a bit suspect. Same day, same box, in the STOCK bbl... drum roll please... 1108 fps for 4 shot avg. No smiles, but some pieces of brass have a slightly shiny spot with a familiar curve to it...

So for making the gun 1/2" longer, and working with the tight chamber, I am gaining 46fps with an ultra-heavy lead bullet. On the one hand, that is half the difference in speed between bullets that weigh 20g different in 10mm. On the other, is anything that gets hit going to know the difference?

Oh, interestingly enough, the same load showed flatter primers in the stock barrel. In the AM barrel they are still rounded on the edges, in the stock they are quite flat.

Tried for accuracy with the stock barrel, It seemed much more accurate for the first 5 rds, then groups opened up as it began to lead. With other cast bullet loads that didn't lead the barrel, the stock barrel did really well, it is the leading that loses the accuracy.

Just for fun, that difference of 46fps makes a difference of 52ft/lbs of muzzle energy and 1 lb of free recoil energy.

Last edited by Any Cal.; 01-22-2013 at 03:27..
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