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Does anyone know a approximate barrel velocity for 7mm08 out of a 16.5 inch barrel
factory 140 grain bullets (Remington corelokt)
the factory has it at 2800 out of a 22 inch
trying to calculate a drop/energy chart for hunting
eg how far out bullet will expand properly for a ethical shot
i do not have access to a crony
at a guess 2500 with 308 factory ammo 147 gn velocity out of 24 inch barrel is 2780 out of my 12 inch 308 it is 2200 out of my 16 inch 308 is 2450
https://rifleshooter.com/2014/12/308...ty-28-to-16-5/
25 FPS per inch
Use this as a reference, but it all depends on your Ammo choice and individual barrel. Chrono is recommended for accuracy, however you can use the @Gibo method of shooting at distance and calculating the drop to determine FPS from the muzzle.
Either way I would recommend you shoot some steel/rocks/targets at the farthest distance you intend to take a shot on an animal to make sure you can hit what your shooting.
Do you own a range finder?
I run a 15" barreled 7mm-08 for bush hunting. I use 140gr NBT handloads with a stiff load of CFE223 and get 2700 fps. Id say the factory loads would be 2400 to 2500 at a push.
Best thing to do is just get out and shoot it out to 300 yards or what ever distance you want to use it to and record the actual drop, then setup from there.
No substitute for real world testing in my opinion. At the end of the day knowing the speed is irrelevent, knowing where it goes at different ranges and being familiar with the firearm is.
CFE223 is a great powder for the short 7-08. You can substitute it with BLC-2, but its quite a dirty burning powder.
For mine with 18" barrel 140 grn Berger @ 2800 and 120NBT @ 3000fps. I'm using the 120's successfully. I used the 120 Sierra for many years right from when the 7-08 first appeared in NZ.
With the NBT one heavy mature red stag last year after the roar at 400 yards - shoulder shot - bullet was in the opposite shoulder. He ran 20 yards down hill dead on his feet. Have shot quite a few deer in the 300-400 range with them and never had a problem. The 120NBT is stout and works at bush ranges too.
Ummm, what was the OP's original question again? I got a bit carried away there.
A mate says he's chronied his 18" 7mm08 with factory winch ballistic Silvertips at 2550.
Most reliable way is to shoot at 100m and 300 m on the same day with same ammo and choose a velocity that fits your trajectory. It will save you heaps of ammo and petrol in the end. A rangefinder will also help a lot if you try and shoot past about 200m.
I say 100 & 300 because your 100m group will be small enough to get a good idea where it is and you've got enough leverage to estimate trajectory difference . Not so much drop between 200 and 300 and you won't be able to pinpoint the groupp centre so well at 200. Ranges dont have to be exactly 100 and 300 as long as you know exactly by rangefinder what they were. Eg 67m and 284m would be fine. Shots on paper will also tell you how far you can realistically hit something under favourable conditions. Take a minute to look where the shots fall in your reticle at max mag too and write it down.. who's getting carried away now ?
trying to calculate a drop/energy chart for hunting
eg how far out bullet will expand properly for a ethical shot
i do not have access to a crony[/QUOTE]
Most standard bullets need a velocity of 1800fps on impact to expand reliably, You could use SST's they are designed to expand at long ranges
should be Ok at reduced velocity.
thanks guys
ive never shot anything more then 150m
just want to figure out what i can do should the opportunity arise
What part of the country are you in Muka?
139 horn sst BC.486, win748 powder 44.4gr , std primers,fed.brass, 2700fps +2'@100yds 0@ 200yds in Tikka 595 16.5' barrel
or
39.5gr BM2 2650fps
Helensville, AucklandQuote:
Originally Posted by Gibo
If you would like to do a day trip to Rotorua we have 2 shoots a month out to 300m at the local Deer stalkers range that would help you a lot.
You could write down your drop at 200 and 300 and I also have a chrony that you could use to workout a card to 400, which will be about the limit for a 16.5in barrel
Our shoots are pretty informal with all sorts of rifles turning up so don't be put off thinking we are flash target shooters, one day we had a guy shooting 300m with a open sight SKS resting on top of a block of wood and a paint tin and hitting the target.
Cost to non members is $10.00
Thanks Winaa , i will PM you next time im in the bop