velocity estimation

[vaeevictiss]

Ive seen some people on here using some piece of software that gives a pretty decent velocity estimate for a round...i seemed to have found my perfect load, as it is shooting 1/4" groups at 100yds. What i do not have is a chrono (i know i know, its on my midway wishlist lol).

It would be great if i could get some kind of estimate from someone with that program...

details

remington 700
22" bbl
1:12.25 twist (measured with the cleaning rod/dowel method...really hoping i woulda got lucky and it went the other way so i can have more luck with subs lol))

Lapua brass
Federal LR primer
44.7gr Varget
178gr A-max
2.910 COL (seated 0.0020 off the lands)

im sure i missed something, let me know if more info is needed.

I really appreciate if anyone checks this for me.

 

[Temp9]

The program is called QuickLoad. I highly recommend you purchase it. It's a fantastic piece of software. In the meantime, the owner of QL has requested that no one requests data who hasn't purchased the program.

 

[Niles Coyote]

I use 44.5 varget with Winchester brass and a 175 smk and my numbers in a 20” factory Remington barrel are 2550 and same load in a 26” is 2645. When I tried the load in my 20” substituting the 178 amax IIRC it ran about 10 fps slower... so with .2's more powder in Lapua brass and a 22" factory barrel my SWAG is you would be around 2575-2625 range.

 

[One-Eyed Jack]

You can use the JBM ballistic calculator to estimate your MV by shooting to long range, noting the elevation needed to hit the target and the usual environmental conditions (altitude, temperature, pressure, humidity). Run the calculator with a series of MVs until it outputs your measured elevation.

QuickLoad is an excellent tool, but there are real-world variations in barrel friction that it cannot predict. Some barrels are slow and others are fast compared to the nominal QL barrel model.

 

[vaeevictiss]

oh wow thats a pricy piece of software...i mine as well just spend that 150 on a chrono haha.

 

[One-Eyed Jack]

I use 44.5 varget with Winchester brass and a 175 smk and my numbers in a 20” factory Remington barrel are 2550 and same load in a 26” is 2645. When I tried the load in my 20” substituting the 178 amax IIRC it ran about 10 fps slower... so with .2's more powder in Lapua brass and a 22" factory barrel my SWAG is you would be around 2575-2625 range.

Are these measured numbers? I think so, but you didn't state it. QL would predict a slightly higher MV at least for the 26" barrel, as I use the same load in my GAP rifle and have done QL calculations of it. I recall concluding a few years ago that Remington barrels were slower than nominal and Rock barrels were faster.

 

[Niles Coyote]

Are these measured numbers? I think so, but you didn't state it. QL would predict a slightly higher MV at least for the 26" barrel, as I use the same load in my GAP rifle and have done QL calculations of it. I recall concluding a few years ago that Remington barrels were slower than nominal and Rock barrels were faster.

Yes on my magnetospeed and cross checked at distance on jbm drops with current conditions. The kicker, my 21.75" rock creek barrel sends the same load +/- a few feet per second of the 26" Remington factory barrel... and my 26" Winchester stealth... again same load accept OAL had to be change this time for the much shorter chamber (2.825ish down to 2.780ish for about a .01" jump)... 2690-2700fps

Did I mention I have too many 308's???

 

[One-Eyed Jack]

Did I mention I have too many 308's???

I came to that conclusion for myself a couple years ago. 308s are great for learning about wind and other long range basics because the 175SMK doesn't have a high BC, then you can shoot more capable rounds like the 260Rem and 6XC. From now on, just say NO to more 308s! End of off-topic comment.