CFE 223 vs IMR 8208

[Boondoggle]

I've done a bunch of reading here and have googled myself into a stupor over how temperature sensitive CFE 223 really is. I'm going to be running one of the Faxon 16" bulk buy barrels so the extra velocity is appealing over IMR8208.

Obviously accuracy trumps all in the long run so I'll try both powders unless the temp issue with CFE 223 is a big deal. I'm hunting in the SE US ( deer and hogs) so there's potential for a significant temp swing from deer hunting in TN in the winter vs a late spring hot hunt in FL.

Thanks in advance for all the help and advice.

[NugginFutz]

There's this. Not the last word, to be sure, but includes some real world data.

http://www.65grendel.com/forum/showthread.php?11196-Powder-Burn-Rates-and-Temp-Sensitivity&p=123108&viewfull=1#post123108

[JASmith]

Nugginfutz' table allows us to approach the question semi-analytically.

First, determine rhe max and min temperature you expect to shoot in. The highest temperature will form a basis for your maximum safe load. Subtract 1.7 fps for each degree between the max and min temperatures (verify with the table - we are all victims of typos!).

Next, run two calculations in your favorite ballistcs app. You are looking for the difference in drop at the maximum ethical range for your hunting. The mid point should be your approximate zero if you plan to leave sight settings alone.

Last, ask yourself if the difference beteeen mid point and the extremes is more than about 4-5 inhces. If not, youu are likely good to go for medium game.

Alternatively, adjust your sight settings for both mv snd exterior weather. More hassle in the field, but some feel more comfortable with the arithmetic in stressful environments.

[Boondoggle]

So running some numbers for the 123 gr SST, with a 50 degree temperature difference I'd have about a 1/2 moa drop which at 100 yards is an inch and a half. Based on that math it seems I should give it a shot?

[JASmith]

The moa difference will grow with range, but you may still be OK at 300 yards.

How far out do you plan to shoot?

Run the numbers for that range to verify.

[Boondoggle]

The moa difference will grow with range, but you may still be OK at 300 yards.

How far out do you plan to shoot?

Run the numbers for that range to verify.

300 yards would be the longest shot I'd take. Ballistic calculators average just under a 1/4 MOA at 200 and just under a 1/2 at 300. I think I can live with that if there's decent extra velocity and it's as accurate.

[BoxofRox]

So running some numbers for the 123 gr SST, with a 50 degree temperature difference I'd have about a 1/2 moa drop which at 100 yards is an inch and a half. Based on that math it seems I should give it a shot?

Just wanted to make a small correction incase you've based other numbers off of it, 1/2 moa at 100yds isn't an inch and a half.

[Boondoggle]

Yes sir correct. The inch and a half was for 300 yards

[454bore]

I would think that you could go up .3 grains for cold weather and not have a problem since CFE is very good on not being a powder that spikes with a small increase in weight.