Is someone with Quickload able to give me a MV estimate for my 308 shooting 165gn Nosler BTs.
Tikka T3 chopped to 16". Load is 43gns of AR2208. Not sure what other info is needed but let me know if you can help.
Thanks.
Is someone with Quickload able to give me a MV estimate for my 308 shooting 165gn Nosler BTs.
Tikka T3 chopped to 16". Load is 43gns of AR2208. Not sure what other info is needed but let me know if you can help.
Thanks.
Experience. What you get just after you needed it.
Need your case capacity in grains of water and OAL to be more accurate.
At a stab in the dark I used default case capacity of 56.0Gr and 2.8 OAL and it comes to 2430 fps (would be 2662 in a 24")
BC doesn't matter, until you need to dial
OAL is 2.800 inches. Is case capacity a simple matter of filling it with water and weighing the water?
Experience. What you get just after you needed it.
Weigh a fired case with primer in, then fill with water weigh again. take empty weight from full weight should be 56Gr or more.
BC doesn't matter, until you need to dial
77gns water.
Experience. What you get just after you needed it.
BC doesn't matter, until you need to dial
Sorry. Typo. 57 gns water (not 77).
Thanks for that. Just wanted a good estimate before I go out and verify it at distance.
Hypothetical question here.
If, when verifying drop of a load, you discover it is different from what is expected (using measured MV and published BC) would you alter the MV or the BC to get the correct trajectory? Or does it matter which you change?
Experience. What you get just after you needed it.
MV, not BC (assuming you've got a realistic one for the pill you're using, some are "exaggerated".) Litz has publised some good data on real world BC's.
But its also likely that your scope may not exactly move in moa (or mils if its metric) as the graduations say. So the error in drop vs dialed might be MV but could also be scope calibration. A lot of "moa" scopes dial "IPHY" (inch per hundred yards) or less, rather than "moa" 1.05 in per hundred yards. You can calibrate your scope dial up by placing a box with inch graduations (10 - 12 inches) at exactly 100 yards (from turret to box) with the rifle held in a fixed, stable position then dial up 10 moa and measure where your POA shifts to. If it shifts down 10 inches exactly then its dialing IPHY. If its moving 10.5 inches then its moving MOA. Some maybe be less than IPHY. Either way you can derive a correction or calibration factor. If your intended shooting range is > 500 yrds then calibration probably not a big factor.
Thanks for that. 500 yards would be an absolute max for me and that rifle. Scope is a VX5 so I assume calibration will be IPHY, not true MOA.
Is Litz's data available on line?
Experience. What you get just after you needed it.
Yip definitely adjust velocity. Bryan Litz has the 165 NBT BC at 0.444 G1 and 0.227 G7.Thanks for that. 500 yards would be an absolute max for me and that rifle. Scope is a VX5 so I assume calibration will be IPHY, not true MOA.
Is Litz's data available on line?
Nosler usually have over estimated BC's taken close to the muzzle.
The cheapest way to get access to Litz's data is you by the Applied Ballistics app
BC doesn't matter, until you need to dial
Thanks, that's excellent info.
Is there a reason to adjust the MV as opposed to BC or is it just the done thing? If the published BCs are wrong anyway would it make a difference to the trajectory outcome adjusting the BC? (not that I care which one I adjust, if I have to, just trying to understand the process).
Experience. What you get just after you needed it.
Short answer:- Because Bryan Litz says so!Thanks, that's excellent info.
Is there a reason to adjust the MV as opposed to BC or is it just the done thing? If the published BCs are wrong anyway would it make a difference to the trajectory outcome adjusting the BC? (not that I care which one I adjust, if I have to, just trying to understand the process).
Slightly longer and more informative answer:- The team at applied ballistics found while doing testing with very expensive and "Lab calibrated gear" that you get best results truing the velocity first and then do a second truing of BC past the subsonic range if you intend to shoot that far.
For the average hunter shooting inside 500, you could true either and get good results.
the reason I suggested Muzzle velocity for you is Quickload is only a stab in the dark and the Ltiz BC I gave you will be much more accurate, (True the least known factor)
So if I had a speed form a loading manual and a factory BC I would true Speed
If I had a Chronographed Speed and a BC from bullet manufacturer I would true BC first.
If I had a Chronographed Speed and a tested BC I would true speed.
Remember BC sell bullets, so never trust a manufacturers data
Last edited by winaa; 05-06-2020 at 11:47 AM.
BC doesn't matter, until you need to dial
Bookmarks