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Disturbing Chrono Results


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Went out the range today to do some quick chrono checking on some loads and got some very odd/weird/disturbing results. Thought I'd run it by the consensus here...

.45ACP

4.8 gr N320

200 gr Rainiers

1.260" OAL

WLP primers

The starting load from VihtaVouri is 4.7gr and should yield 888FPS, give or take, which is perfect for me, should give me a nice cushion of PF.....but....10 shot average was around 713fps!! :surprise:

It was cloudy out today and I tried chronoing repeatedly with and without the skyscreens on my Gamma shooting Chrony. Very similar results with either. Yes, I was 10-12 feet away. Yes it had a BRAND NEW battery.

Other than my chrono just being completely wacky, I cant think of what could cause this issue?!?! :unsure: I did not have any other ammo with me to chrono to double check anything, but will try to do that Monday after work.

Any suggestions!?!?!?!? :mellow:

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Published data is usually conservative for legal reasons but that seems a bit too much off.

Try the same load with a jacketed bullet and see if the results change. Bullets might be a bit undersized for your barrel.

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Dont load the 200 but my load is

N320 5.0

haps 230

OAL 1.220

win brass

CCI large pistol

Gives me 172 PF from a glock 21, Vihtavouri uses 6 inch barrels for there test.

Edited by sauza45
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This is no help, but I've had frustration getting Ranier 200 gr bullets up to PF. In fact, I haven't found a load that has even gotten them up to 800 fps. They group very well, just haven't found a load that shoots them fast enough.

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FWIW, the 200 rainier load that I used in my 5" SA with a Kart barrel needed about 5.2 gr of N320 to make ~171. The OAL was 1.245. WLP. Brass of unknown origin. 12,000 rounds later I was up to 5.4 gr!

Later,

Chuck

Corey, I just saw your last post. I loaded longer at first but quite a few people who were .45 old timers told me that 1.245 was the sweet spot for function. That let's the bullet hit the barrel hood in about the same spot as a 230 RN.

Edited by ChuckS
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I decided to try N320 for .45 and found that I needed to add nearly a full grain more than published loads to achieve anything close to published results.

Using Precision 200s at 1.22 OAL, 5.0 grains got me 688 fps, 5.4 got me 800 fps, and I finally had to go to 5.75 gr to get a comfortable 862 fps. I have a slow barrel, but it isn't that slow.

BB

Edited by bbbean
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Gonna work some different things up tomorrow and test them Monday. depending on what the results there are, I may go back to Titegroup for my .45s for the next couple of weeks. I'm about done shooting my .45 for the year anyway but I got some big matches I need this for.

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made some load adjustments and chrono'd after work today:

-shortend OAL to 1.245" with the same 4.8gr N320 load. Velocities increased a bit, but still way too slow for me. Min 712, max 760, avg of around 730

-bumped powder charge to 5.1gr, Min 731, max 813, avg 760-770. still too slow

-bumped powder to 5.3gr, min 750, max 807. avg 760-770ish again.

This is making me want to rip my hair out!!! :wacko:

I'm to the point where I just want to buy some ammo to shoot the next 2 weeks and then be done with .45 for awhile. Tried AA&A but they are closed tonight and Universalammo.com didnt get an answer.

I'm wondering if some jacketed bullets from MG or something would help me get a bit more velocity. Im going to bump the powder a couple more .1s and see what it gives me and I need to check to see how many 230gr Rainier bullets i have. May try those... if im gonna shoot slow, maybe some heavier bullets will help me.

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Now if i could only get my hands on some Zeros in the next 2 days...

The timing on this sucks. I had 450 rounds of 230/Clays in Illinois for my use at the SSC but since my customer was nice enough to eliminate any possibility of being at the match this weekend, I had my friend send them back. Oh well...

Good luck,

Chuck

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Now if i could only get my hands on some Zeros in the next 2 days...

The timing on this sucks. I had 450 rounds of 230/Clays in Illinois for my use at the SSC but since my customer was nice enough to eliminate any possibility of being at the match this weekend, I had my friend send them back. Oh well...

Good luck,

Chuck

:(

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made some load adjustments and chrono'd after work today:

-shortend OAL to 1.245" with the same 4.8gr N320 load. Velocities increased a bit, but still way too slow for me. Min 712, max 760, avg of around 730

-bumped powder charge to 5.1gr, Min 731, max 813, avg 760-770. still too slow

-bumped powder to 5.3gr, min 750, max 807. avg 760-770ish again.

This is making me want to rip my hair out!!! :wacko:

My load book, Lee, shows 200gn jacket start load of 5.5 and max 5.8 at 983 FPS

Lead 200gn start load 4.9 and max 5.5 at 1010 FPS

Could also be the chrono if you are outside in the late afternoon. LED's in a Box is the only way to really be sure.

MDA

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Tested some more loads this morning with 5.0 and 5.2gr of Titegroup.

5.2 got me a min of 805, max of 860, avg of ~840. I'm back in Major now it would appear. Time to load up now....

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Tested some more loads this morning with 5.0 and 5.2gr of Titegroup.

5.2 got me a min of 805, max of 860, avg of ~840. I'm back in Major now it would appear. Time to load up now....

Hope you don't chrono three rounds of the 805! I'd add another 0.1 to be safe.

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Tested some more loads this morning with 5.0 and 5.2gr of Titegroup.

5.2 got me a min of 805, max of 860, avg of ~840. I'm back in Major now it would appear. Time to load up now....

Hope you don't chrono three rounds of the 805! I'd add another 0.1 to be safe.

I hear ya! B)

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Just for the record to to be sure your chrony is working ok, shoot something else thru it like a 22. My shooting chrony has been given me fits. it will read a 22 but won't my 45 even with a screen in front to block muzzle blast. It has a hole in it to shoot thru. This is 2nd time i have sent it back to factory. I am not sure if my loads will make major or not because i can't chrono. Hopefully 5.4gr HP-38 under 200gr Precision RN will work. Ho-pe u have better luck with your shooting chrony than i have.

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  • 5 months later...

I would say that you got one or more bad readings that factored into the average. If you can look at results and remove ones that are way too low as to indicate a bad reading prior to computing the averace, SD and ES. Depending on sun and clouds i have to weed several out for the average.

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  • 3 weeks later...

Went out the range today to do some quick chrono checking on some loads and got some very odd/weird/disturbing results. Thought I'd run it by the consensus here...

.45ACP

4.8 gr N320

200 gr Rainiers

1.260" OAL

WLP primers

The starting load from VihtaVouri is 4.7gr and should yield 888FPS, give or take, which is perfect for me, should give me a nice cushion of PF.....but....10 shot average was around 713fps!! :surprise:

It was cloudy out today and I tried chronoing repeatedly with and without the skyscreens on my Gamma shooting Chrony. Very similar results with either. Yes, I was 10-12 feet away. Yes it had a BRAND NEW battery.

Other than my chrono just being completely wacky, I cant think of what could cause this issue?!?! :unsure: I did not have any other ammo with me to chrono to double check anything, but will try to do that Monday after work.

Any suggestions!?!?!?!? :mellow:

A few years ago I was getting ready for the 2009 Larue three gun match and I was working up some rifle loads. I decided to shoot my 45 acp loads over that I was shooting in IDPA and in Limited 10 and I found out I had been shooting minor the last few years. Embarrassing but you can't trust the books for velocity.

pat

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:rolleyes: Just to confuse the issue. I had similar results with my Shooting Chrony. Sent it in and they replaced the front sensor. Have had reasonable results since. Went to the range yesterday. :angry2: Windy, cloudy, and 60 degrees F. New load using M&P 9mm Pro 5 inch and a 125 TC lead bullet and 3.9 g N320. I got 5 readings and 12 Err 2 before giving up. The low read was 1190, the high was 1345. Average was 1211. Way too high. Usually check with a 22 lr, but forgot it. I was testing some 30-06 loads with 180 g SST using 59 g H4831 and 60 g of H4831. No err 2 for the 20 rounds I shot. Low and high for the 59 g was 2720 and 2957 with average fps - 2790. 2720 was the velocity I wanted The 60 g load got silly. Low and high was 2573 and 3043 with average fps - 2749. 7 readings was above 2900 fps. Too high. The chrony was 15 feet from the rifle. 10 feet for the pistol. I was shooting from 9:00 am to 10:30 am. Any suggestions?

The main reason for the trip to the range was to test the 9mm loads, the 30-06 was to test for accuracy. The 9mm was a bust :blink: and the accuracy of the 30-06 was hunting acceptable. The rifle is a Browning stainless A Bolt. I have a 300 mag of the same make and it blows the 30-06 away in the accuracy department. :huh:

No suggestions on getting another make of chrnograph. Already thought of that. :P;)

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