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164.97 Pf


Harmon

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Titegroup, 4.3 loaded to 1.135 OAL with 180g MG JHP. I shoot a G35 with stock barrel.

The wife's STI Edge made major with Vihta n320. Maybe I'll consolidate and just use one powder for a while.

-Mike

Edited by cnemikeman
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Just a thought on all the talk about using scales in unprotected outdoor environs...

If I'm running chrono, I'm not going to bother with totally shielding the scale from wind etc. for every single round I check. Most shooters build enough of a cushion in that it won't matter. If they look like they might not make their stated PF, then I'll pull out the box to shield things and get serious because if at all possible I want the competitor to make it. Just because you don't see the box being used for every shooter, don't assume it's not handy.

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Titegroup, 4.3 loaded to 1.135 OAL with 180g MG JHP. I shoot a G35 with stock barrel.

The wife's STI Edge made major with Vihta n320. Maybe I'll consolidate and just use one powder for a while.

-Mike

Mike -- just as another data-point, I've used that exact combination of gun, barrel and bullet, but 4.5 grains, and been around 166-171 pf at 3 chronographs (Summer Blast, VA Sectional and NC Sectional); all but the last were pretty warm.

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Thanks for the info. I definitely can see that it's a bit more precise than I had anticipated it being. I load my loads, switch the powder and OAL, and then load for my wife. I'm just glad it was mine and not HERS that didn't make it. It would have been a VERY long ride back to Dallas. :)

-Mike

Edited by cnemikeman
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Loading down to the power floor is just asking for trouble.

It almost happened to me at the 2005 SC sectional where I walked off the chrono stage with a big 165.0 after firing all rounds and doing a "more velocity dance". It was my problem, not a problem with the rules. I think it wouldn't have been an issue if the chrono had been in a "coffin", but I should have used more powder.

It's up to us to show up with a functioning gun and ammo that works and meets the power factor. If we don't then it's time to look in the mirror to find the source for blame.

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Mike, FWIW.... N320 is somewhat temp sensitive, too, IME...

Loading w/ a 185gr Precision Bullet for my Trojan, in the middle of summer, 4.2gr makes 170PF. At DoubleTap last year (as the only shooter to chrono successfully... :D ), 4.7 barely squeaked by at 165PF. That's actually slightly more variation than VV predicts in their loading manual formulas, but its still about the expected curve...

I haven't tested TG in this fashion (or any other powder other than 7625, actually), but... it wouldn't surprise me if it swung that much...

Oh, BTW - welcome to the "minored at an Area match" club :D I bet it won't happen again :D

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Mike, FWIW.... N320 is somewhat temp sensitive, too, IME...

Loading w/ a 185gr Precision Bullet for my Trojan, in the middle of summer, 4.2gr makes 170PF. At DoubleTap last year (as the only shooter to chrono successfully... :D ), 4.7 barely squeaked by at 165PF. That's actually slightly more variation than VV predicts in their loading manual formulas, but its still about the expected curve...

I haven't tested TG in this fashion (or any other powder other than 7625, actually), but... it wouldn't surprise me if it swung that much...

Oh, BTW - welcome to the "minored at an Area match" club :D I bet it won't happen again :D

Dave,

Thanks but I wasn't in a hurry to join that club. :P I'm loading Patty's gun at 4.9g of n 320 loaded to 1.200 OAL with 180g Montana Gold JHP. It dropped a little, but she still made major. I do want the box of once fired primers as my prize for closest on the chrono yet not making major. :D:D:lol:

Update on this:

I went out this morning and took my chrono and my ammo and re-did the data.

The temperature this morning was 42 degrees, with 'feel like' of 38 degrees and sunny.

It was a bit warmer than on Saturday, but not by much. My data from this morning:

Dec 4th, 2006 10:42 AM 42 degrees & sunny

Glock Factory Barrel G35 4.3G-Titegroup 180 MG JHP

958

942.8

956

946.8

934

950.2

947.7

956.3

941.7

948.2

954.5

948.74 170.7741818

Might be time to compare my chrono with another brand and see how close they are.

-Mike

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AT the Limited Nats we had 3 shooters in my squad that were using the P Delta ammo...

One had 165.07

The other two ended up at 166 and 166.5..

They all ended up shooting all nine BB's with the highest 3 going for the average...

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I had been running 4.9 of 320 behind a 180 for a couple years. Usually around 170, Just before the nationals, I chrono'd and to my surprise, same load was down to 163! No difference in powder lot, primer lot or head lot. Bigger surprise, it still was seriously major in my back-up gun. Seems that when the barrel went, it went quick! I had to bump up to 5.2 to make a comfortable 171, and went over 180 in my back-up gun. New barrel, back down to 4.8 grains, and may go a bit lower yet, been busy so I have't had time to work it all out yet.

Jim

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I declare that from now on, anybody that says "you shouldn't be that close" on PF is no longer allowed to argue that PD trigger pulls are too hard to measure. :D :D :D

I declare..bite me. :):):)

If you read what I said...I think the chrono procedure sucks and is a PITA for match officials...just like the trigger pull crap would be. (Hey, I hear Open division is next...)

:P

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  • 2 months later...

Just a quick follow-up -- found out that my Shooting Chrony reads fast compared to a match grade CED Chrono....... so make EXTRA sure you know where you really are, and stay away from too close to the PF. I really thought I was at 170, which gave me fudge room, but the numbers showed differently. I am now wiser for it, and hopefully can pass the info on to others so they won't suffer the same fate. I also now chrono on on CED. :)

-Mike

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More fun-with-chronos:

I've been noodling around with some ideas for chrono calibration. If I got my math right, did you know that for skyscreens spaced 18 inches apart, the travel-time difference between a bullet at 1000 and 1000.1 fps is 150 nanoseconds? Know how far light goes in 150 nanoseconds? Barely 50 yards. Know how far a 1000 fps bullet goes in 150 nanoseconds? 0.0018 inches.

Something tells me that $100 chronos aren't going to be accurate to two thousanthds of an inch over 2 feet, especially as a 2 foot steel rod changes length more than .002" with a 20 degree temperature change, and that doesn't include all the other possible error sources in detecting a bullet flying by.

Executive Summary: it's all voodoo and anything after the decimal place is most likely completely random.

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Just a quick follow-up -- found out that my Shooting Chrony reads fast compared to a match grade CED Chrono.......

I've got a Shooting Chrony myself. It's reasonably close to Oehlers I've compared to, but I haven't had an opportunity to compare to a CED. How far off is yours from CED?

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Just a quick follow-up -- found out that my Shooting Chrony reads fast compared to a match grade CED Chrono.......

I've got a Shooting Chrony myself. It's reasonably close to Oehlers I've compared to, but I haven't had an opportunity to compare to a CED. How far off is yours from CED?

It's running anywhere from 10-20 fps. I wouldn't think they are all that way, but mine is...... and the CED I used was the actual match chrono from Area 4 a couple years back.

I've switched to n320 anyway, but I'll get to see if I'm right at the DTC this year. :)

-Mike

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