Here's the REAL story,pellets VS powder

[rks1949]

I set the crono up today for some "real world" testing with T7 pellets,and T7 2F loose powder. It has been mentioned that 120grs. of T7 equals the 3 50gr. pellet load. It dose NOT! I shot a string of 5 shots of each over the crono today. The veloocity figures are for the average of each five shot string. The crono was 10 feet in front of the muzzel,and a strong head wind actually blew the smoke straight back( finally found a good use for the wind while shooting). The first string of 5 were 120grs. T7 2F over a Hornady 250gr. SST with the supplied sabot. The average velocity was, 2154 fps. with a standard deviation of 31fps. I was really suprized at the deviation,many center fire loads don't have that good of a spread. The second string of 5 shot was with 3 50gr. T7 Pellets,over a 250gr. SST with the suplied sabot. The average was, 2217fps. with a standard deviation of 51pfs. The diffrence between the two loads is 63fps. velocity! After crunching the numbers into the Serria Infinty Ballistics Program, I came up with some intresting numbers. The pellets DO shoot flatter,but the diffrence is almost nothing. At 100yds -0.18 @150yds.-0.08 @200yds.-0.29(that's a little over 1/4 inch) @ 250yds.-0.87 (around 7/8 inch). Now I have to figure out,can I add 5grs. more powder,and equal the 3 pellet load? Or a better question is,is it worth the effort to gain 7/8 inch flatter trajectory @ 250 yds.? Also why was the powder more consistant than, the pellets? Here's the print out's. To view them larger just press your control button and roll your mouse on them! Ron

 

[toytruck]

Very interesting!! Did you weigh the charges of loose T7 by volume?

Compaire your findings with Hodgdon below:
http://www.hodgdon.com/tripleseven/slideshow/page13.php

I couldn't find a chart there to match yours, but this shows velocity. Loose powder should be more powerful and therefore more accurate than pellets, I would say due to the fact you can adjust the loads with loose powder and not with pellets.

 

[cayuga]

toytruck.. you had the same thought as me.. weighed VS powder measure. Very interesting test. Thanks very much for the effort. That is the kind of information I like to read as it gives me good ideas of loads and what other projectiles MIGHT do. I really have to get a chronograph. I think Santa knows all about that though.

 

[rks1949]

Yes all the loose powder loads were volume weighed. I've thought of trying 5 grs. more loose powderto see if the velocity would equal the pellets,but it really isn't worth the effort!

 

[rks1949]

Your welcome,Guy's. I just got tired of looking in books for the velocity to enter into my ballistics program. They all give diffrent numbers. When I used their numbers to plot the trajectory,it never worked out. On a side note: after getting the real #'s my trajectory is spot on. I zeroed the gun to hit 1 inch high @ 40yds. and it's on the money all the way out. I like this program,I've used it for 4 years on my varmit rifles,and it hasen't lied to me yet. It really makes setting your zero easy,and it works. Ron

 

[toytruck]

Good luck Dave, hope Santa is listening.... :lol:

rks1949, Everything I have read says that 120 loose T7Fg is the same as three (150 gr.) T7 pellets, but your charts show different. Thanks from here as well for the effort. 8)

 

[cayuga]

I must have missed it.. what rifle and primer were you shooting? Barrel length also if you please.

 

[choc-dog]

your results

Thanks for your chongraphing results. The velocity difference between the 3 pellet VS. loose powder has more of an effect on FT. LBS. than it does on bullet drop.

It's the same for centerfire rifles.

Choc-dog

 

[rks1949]

Dave,it's a Prohunter with a 28" barrel,and Cheddite primers. Ron

 

[rks1949]

I think I'm gonna stay with the loose powder load. I can't really shoot good enough to make up the diffrence. Ron

 

[rks1949]

toytruck, for all practical purposes,they are the same. Heck 7/8 inch @ 250yds. and 63fps. isn't enough to worry about. I can't even hold that close at that range. I noticed that Hogdon dosen't list any load over 100grs. Their pellet data is the same too! I guess that is a marketing trick to get ya to buy pellets,but they don't show using over 100grs. in any of their loads. I noticed this on the pamplet that came with the pellets.

 

[rks1949]

Another use for the Ballistics Program is, once you have your trajectory plotted,and the known drop at various yardages. You can use Windows Note pad,or Word to print out a sticker for your gun stock. Then when out hunting,and spot a target,you can use your range finder,read the yardage,and look at the sticker,and hold for the correct trajectory to place the shot where you want it. The symbol "D" on the sticker represents the wind drift,for a 10mph cross wind at the various yardages.

 

[meathunter1]

This is probably one of the most informative posts I've read regarding loads, powder and velocity. Thanks.

 

[Tracker12]

What would be nice is to weigh each of the pellets to see if there is any variances. Also to get a really accurate read on the loose powder you would need to do the same weigh it. Volumetric charges have built in variances.

 

[Corncob]

Very interesting post....thanks for your documentation. Just b/c I have too much money, I think a chronograph is in the future. What was most interesting were the drift compensations. I shoot heavier bullets 290 TMZ & 300 XTP and do not have an accurate wind gauge. In the early fall, we get some pretty strong south winds and I shoot east to west. My experience showed only an inch of drift at 200 yards with a stout crosswind. Less drift is one reason I went with the heavier bullet, but the difference is quite a bit more than I would have guessed.

BR's Cob

 

[rks1949]

Corncob,yeah, the heavy bullets do better,at "bucking the wind". We do allot of coyote hunting in the off season. And have found that most long range shots are missed by not judging the wind correctly. Most shots are dead on on trajectory,but miss behind,or in front of the coyote. Those little .22 bullets shoot flat,but blow around in the wind allot at long range.