SS Nationals - Minor Town

[Nik Habicht]

BTW. no need to blame the Chrono when most everyone else made declared PF. Test your match ammo before you go.

I believe that's what people did and found a pretty good size difference between home and the match.

Were they comparing apples to apples? I.E. ammo loaded with Powder from lot A, bullets from box B, primers from lot C, and loaded in new or known once fired brass from the same manufacturer? Were the rounds loaded during a single loading session? Were they run over a chrono of the same type in the same temperature conditions? Were the skyscreens the correct distance from the muzzle?

Have a variable in any of these and you could well have a variation in power factor......

[BillD]

BTW. no need to blame the Chrono when most everyone else made declared PF. Test your match ammo before you go.

I believe that's what people did and found a pretty good size difference between home and the match.

Were they comparing apples to apples? I.E. ammo loaded with Powder from lot A, bullets from box B, primers from lot C, and loaded in new or known once fired brass from the same manufacturer? Were the rounds loaded during a single loading session? Were they run over a chrono of the same type in the same temperature conditions? Were the skyscreens the correct distance from the muzzle?

Have a variable in any of these and you could well have a variation in power factor......

Yes, I'm aware of that. I'm saying the guys that have a tried and true load they've been using for years reported a 4PF or more drop in that load from their chrono to the chrono at Nats. This isn't all that hard to understand.

[Gary Stevens]

Checked just prior to leaving for the match at 170. Checked at the match at 172.

[jrb06]

So the question that was brought up in our squad was, How do you check for chrony accuracy and how would you or what would you use to calibrate it? Now if you can calibrate and check accuracy somehow all questions would be answered. There has to be a away or simple tool that can be used to check one. Radar detectors use a simple tuning fork (yes I know it is a different concept but still a simple way to test) so I would think the factory has some way to verify them when built.

[pjb45]

I used a CED Chrono. My powder is VV320.

With the exception of a really cold day for a National match in Tulsa, my Chrono, using daylight, has been pretty much spot on with the Chrono at A2, WSSSC, and Nationals. I had six years of chromo data which confirm my assertion.

VV 320 was temperature sensitive to a degree. Tulsa was very cold and the next National match the weather had warmed up. I made major in both matches but the margin was smaller on the cold day.

My Nowlin and Kart barrels are very close in terms of bullet velocity. My Schumann is about 15fps slower.

As a side note, Taran was building a load for a National match. We shot rounds though his Schumann barrel, then my Kart. The Kart was faster.

[Nik Habicht]

BTW. no need to blame the Chrono when most everyone else made declared PF. Test your match ammo before you go.

I believe that's what people did and found a pretty good size difference between home and the match.

Were they comparing apples to apples? I.E. ammo loaded with Powder from lot A, bullets from box B, primers from lot C, and loaded in new or known once fired brass from the same manufacturer? Were the rounds loaded during a single loading session? Were they run over a chrono of the same type in the same temperature conditions? Were the skyscreens the correct distance from the muzzle?

Have a variable in any of these and you could well have a variation in power factor......

Yes, I'm aware of that. I'm saying the guys that have a tried and true load they've been using for years reported a 4PF or more drop in that load from their chrono to the chrono at Nats. This isn't all that hard to understand.

And it's also meaningless......

I've run a tried and true load for years, and it's chrono'ed differently at different major matches. In fact one year I loaded a 1,000 rounds to take to the Mid-Atlantic Sectional and the Nationals, in one extended trip. That load chronoed at 133 at home, and at power factors from 129 to 137 at the different matches it eventually wound up being shot at. (I had about 450 rounds left over, so I saved it for the next couple of majors....) It was shot over different chronos, at different distances (sometimes the second chrono from the muzzle was faster), in different ambient conditions......

If we're talking Major rounds with 230 grain bullets, there's only about a 35 fps speed difference between a 165pf and a 173pf load -- so a four PF drop only requires the average speed to drop by 17.5 fps. That's not a ton of cushion.

Best practice is to shoot 5-10% of what you load over the chrono, and to reject any batch in which each individual chrono round does not make power factor. Have a single round that dips below 165 PF -- don't bring that batch to a major match.....

[jrbet83]

If I remember correctly, sevigny went 164 last year with ammo from the same lot that shot 170 the week or two before at another match.

Seems interesting that at ss nationals this is a common issue/complaint, but not at limited/open/production/limited 10 nationals, or any area match. If they're using the same chronographs from year to year (which a lot of times they do), they may have a slight issue with their chronos or set-ups. Just doubt its a bunch of shooters b+tching, when it seems like its just at this match.

[Parallax3D]

I'm assuming that they will be using the same chrono setup at Area 5, since it is also at PASA. So, if 10-15% of the field goes minor at A5, then maybe you'd have an argument for the chrono being the problem. Then again. they used the same chrono for the Rev. Nats, the next day, and I didn't hear about large groups of people failing to make PF.

[ltdmstr]

Most people have enough of a cushion that they're going to make major even if the chrono is a bit off. But when you run 172 from the same ammo at multiple matches and with several different chronos for your own testing, then run 168 at the match, I'd say something's up.

[jrb06]

So does anyone know how you would check the accuracy and calibration of a chrono? We have a box for gun size a gauge for mags a ruler for holster and pouch location we can call for calibrate on steel but how do we know the chrono is correct?

[jrbet83]

I'm assuming that they will be using the same chrono setup at Area 5, since it is also at PASA. So, if 10-15% of the field goes minor at A5, then maybe you'd have an argument for the chrono being the problem. Then again. they used the same chrono for the Rev. Nats, the next day, and I didn't hear about large groups of people failing to make PF.

Not necessarily proof one way or the other. At SS nationals, I'd guess 90% of the shooters were shooting 230gr. At area 5, maybe 10% will. If your chrono is reading 20fps slow, that's 2.5pf for Open/Production, 3.5pf for Limited and 4.6pf for SS. Being that the standard cushion is 5pf (170pf), you can see where a slow reading chrono could really have you cutting it close at 230gr.

I don't shoot SS Nationals, so I have no dog in the fight. Just think it should probably be atleast looked into, when so many shooters had issues 2 years in a row (may have actually been more than 2). From shooting in the rifle world (and through research), it's well know that chronographs aren't "right on". +/- 30fps is not unheard of in tests/reviews/comparisons that I've seen.

[Craig N]

At least USPSA doesn't just add 50 fps to everyone if they have chrono "issues".

[ltdmstr]

I highly doubt anywhere near 90% were shooting 230g for SSN. There were plenty of folks shooting .40 for major and 9mm for minor.

[jrbet83]

I highly doubt anywhere near 90% were shooting 230g for SSN. There were plenty of folks shooting .40 for major and 9mm for minor.

Thanks for your help, I only counted to the top 100, and there was only 7 minors and didn't think .40 was that popular, but points still valid.

Edited May 13, 2014 by jrbet83

[jrb06]

I think you would find 40 was well represented. In our squad alone there was four shooting 40.

[JakeMartens]

And 200gr swc

[Parallax3D]

So does anyone know how you would check the accuracy and calibration of a chrono? We have a box for gun size a gauge for mags a ruler for holster and pouch location we can call for calibrate on steel but how do we know the chrono is correct?

Calibration of the chrono is covered in appendix C2 of the rules.

[pskys2]

My 38 short colt went 844@50deg. (840-852)(135PF) w/160 Bayou's in 3 shots. Exactly what I expected from a cold gun, 1st shot of the day chrono. But my buddy shooting Major w/230's had his first shot go 1165 on 1 screen and 788 on the other, then the next 2 settled down and he made a 183+pf. But my guess is there's something going on with the screens/set up. That 1165 sure looked like a sound or light issue, possibly a loose connection on one of the screens.

Edited May 18, 2014 by pskys2

[Norther]

Didn't shoot SS Nats this year, but did the previous 2. My ammo always chrono'd considerably hotter there, like 5-8 pf. For the revo nats last year too.

[bthoefer]

Last year I had a chance to talk to Sevigny after nationals. He said he was one of the only top guys running a 45, that everyone else ran .40 in single stack.

[jcc7x7]

My ammo went 2 PF higher at the Nat'l. Using WST which is supposed to be reverse temp. sensitive. It was Saturday after lunch real nice sunny and warm. didn't check temp. but like I said it was nice out.

Sorry to all who went minor especially the guys who bought ammo

[jcc7x7]

4 out of 8 in my squad were shooting 40's all of us went major. One gent was shooting a 9mm mnor. Had a great squad

[CDPMatt]

Actually, I was higher. 174pf at home to 180 at SS nats. I do use WST though. Maybe Altanta arms should add some powder. Then again, powder is hard to come by.

Sent from my iPhone using Tapatalk

Edited June 9, 2014 by CDPMatt

[TGO]

Gotta forget about power factors guys and focus on velocities. If you shoot a light bullet, you will have a greater margin for error on the chrono when loaded to the same power factor as a heavier bullet. 170 power factor is only 22 fps higher than 165 with a 230. 200 grain bullet, 25 fps. 180 grain bullet, 28 fps. However that's only 6 fps different between 180 and 230.

I chronograph a lot here in az. I never go by power factor, but by the velocities needed to make the factor. intentionally loading or accepting a load that only makes major is not safe. Different days with different temps on 2 identical chronographs for each shot at the same time routinely show 6-8 fps differences in speed between the two identical chronos, and averages of 10 to 15 fps from. This is an average. The high and low extremes are more like 20-30 fps. That is easily the difference between making 170 pf and not making 165. Kids, you can't feel a 5 pf difference with a 230 grain bullet. Or a 200 or 180. You can notice going minor very easily.

I use this system; I shoot 10 shots, discount any single super high or low shot and take that average. If I still have a large extreme spread, I go back and work on the load until es is no more than 20-30 fps Max. I then load up until my slowest of the accepted average, and never remove a shot unless it is obviously a bad round, makes the needed average by 20 fps minimum. this is repeated many times until I never have a low shot less than 20 fps over the lowest speed needed. My averages usually then run around 35-40 fps minimum, over the slowest speed. If I am having wild speed variations, It's nearly always a powder issue, either too slow a powder or inconsistent metering on the press.

Using this system you will probably never have an average under 172 pf. If you then chose to lighten that to lower the pf, you will occasionally, when the odds stack against you, not make 165.

[TGO]

Forgot to mention, I have 3 .40 SS guns and fastest is at least 30 fps faster than slowest. My SS 6" 1911 is 40 fps faster than the SS I shot at Nationals this year. Kippi's 1911 9mm is almost 50 fps slower than my XDm 5.25. So when you are doing this load workup, do it out of the gun you are gonna shoot. My production ammo will not make minor in Kippi's SS gun And the ammo I loaded for the L10 Nationals a couple years ago DIDN'T make major in the SS gun I shot at the Western States SS a year ago.....