tuning a uspsa load for 45acp

[perminator]

what is a good speed to shoot for to stay safely above the minimum 165 for a major power factor load shooting a 230gn cast bullet? i did some chrono testing recently and found 5.0 gn w231 to shoot between 740 - 750 fps which is like 170-172 pf is that a pretty safe margin to make pf?

 

[CB45]

yes, you should be good to go. might run it over another brand of chrono. I've seen wide variation been chrono'ing devices.

I've seen many people go minor at big matches. It is not a pleasant sight to see.

My ammo will vary +/- 3 PF depending on which chrono is used and how it's set up.

 

[Grelber]

what is a good speed to shoot for to stay safely above the minimum 165 for a major power factor load shooting a 230gn cast bullet? i did some chrono testing recently and found 5.0 gn w231 to shoot between 740 - 750 fps which is like 170-172 pf is that a pretty safe margin to make pf?

I'm right at the same speed (4.0 Bullseye, 230 Bayou, 1.255 oal). For me I want to check things again when it is way hot outside & then call it good. Using a second chrony makes sense, but I've checked mine against others & been ok so far so I'm not really excited about that part now.

Shot with a guy last year who loaded a lot closer to the edge on power factor, he made it through the chrono (by a hair) but he was fretting it the whole match. I don't see the logic, but perhaps if I was a better shooter then 165-167 pf versus 170-172 pf would make a difference.

 

[perminator]

thats what i was really wondering about variations in different chronos im using a competition electronics pro chrono what brand is usually used at matches?

 

[Grelber]

what brand is usually used at matches?

Seems like whatever they have. They should (must?) have two set up so there is sort of a built in check for a bad reading.
I haven't noticed any brand variation. I've got an alpha model shooting chrony and it seems to agree with everyone else's. I have seen folks get bad data from failing to insure that the folding chronys are fully opened and that the bullet is not angling across the sensors, or crazy bad data from not having the chrony far enough away & shooting smoky loads.

 

[blkrifle]

thats what i was really wondering about variations in different chronos im using a competition electronics pro chrono what brand is usually used at matches?

most big matches use a chrono box...hence artificial light. this is to ensure consistency no matter what kind of natural light is available. I always try to do my chrono work on a overcast day. seem to get the best results that way. you should be good at 170/172

attended a match in Rolla,Mo. several years ago where nobody made power factor. they finally thru out the chrono stage!

 

[praff]

what is a good speed to shoot for to stay safely above the minimum 165 for a major power factor load shooting a 230gn cast bullet? i did some chrono testing recently and found 5.0 gn w231 to shoot between 740 - 750 fps which is like 170-172 pf is that a pretty safe margin to make pf?

Also one other thing to keep in mind, is that I have found W231 to be somewhat temperature sensitive. I found it to vary as much as 75fps in cold to hot weather. As CB45 suggested, it is good to use a couple different chronos, but it is also a good idea to chrono at different temps.