Range Report what do you get velocity wise with 175 FGMM/20" 9.5 twist barrel
- Thread starter jLorenzo
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Thank you sir. Going to be running a 10x mil dot for now. Max range will be 700, no dialing for lack of trusting scope/1/8th minute clicks. Should be interesting. Have 5 mils of hold over, suppose I could zero another mil or two high above center cross hairs.
I don’t use the box MV, I true it at distance. Do I use the box BC, no. I use Litz’s library on Ballistic AE G7 0.243.
I’m sure there is a fast barrel here and there that may chrono or true out at that MV.
This time of year, shooting at 852’ MSL with temps 60-80 degrees F, 2500 +/- is holding the waterline at distance. Shooting at a much higher DA, obviously results may be different.
I’m sure there is a fast barrel here and there that may chrono or true out at that MV.
This time of year, shooting at 852’ MSL with temps 60-80 degrees F, 2500 +/- is holding the waterline at distance. Shooting at a much higher DA, obviously results may be different.
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I am going to repeat the above because it is really accurate.
The boxes of 175 FGGM I have also say 2600 and I also heard that is from a 24" test barrel. My 26" Kreiger was 2640 after just being spun on, but after it was broken in and speed up, runs them 2650-2660 with their SD. Tnichols 20" @ 2505 and my 26" are examples that the 308 1" barrel reductions have our two barrels within 20fps - well under barrel to barrel variances.
While every barrel will have it's own speed, some much faster than others, you can take about 20-22fps off per 1" barrel reduction to about 16" for a 308 in the FFGM.
There is a guy that actually did an extensive 308 barrel length test that I am sure is easy to find.
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I shot a couple cases of the FGMM Jug load and oddly enough it was about the same, slightly faster if anything. The full chrono report is in the Range and Exterior Ballistics thread under Chronograph Reports with Factory Box Ammo. I didn't continue with them because I didn't have the twist rate to stabilize them properly. Under 750 yards +/- they were very accurate and did well in the wind.
As mentioned above, there will always be variations in speed lot to lot, and every barrel is different as well.
As mentioned above, there will always be variations in speed lot to lot, and every barrel is different as well.
If no chrono, each inch of barrel short of test barrel will be close to 25fps.
Excluding some odd stuff like subs and sbrs.
At some point extra length barrels probably taper off as well. I have not ran any.
There are always going to be exceptions.
Excluding some odd stuff like subs and sbrs.
At some point extra length barrels probably taper off as well. I have not ran any.
There are always going to be exceptions.
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my 24" factory axmc bbl spit out the the Federal Jugg 185gr low 2600ish also. i only remember it about the same as the Federal 175gr. it within 10-20 fps different. it was chrono with magento speed
20 inch rock creek barrel
about 2575 on a good day
Edit: the above is suppressed with a silencero saker
about 2575 on a good day
Edit: the above is suppressed with a silencero saker
I have found that the the FGM Berger 185s run right at the same MV as the FGMM 175s in my rifle ( Bergara HMR w/ 20" barrel)
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