Slow reloads

[Slinkz]

Hey, I just wanted to see if I could get an idea of what kind of deviations exist between different barrels of the same length. As a pre-note, I'm still VERY new to reloading. A while back, I loaded up some rounds so that I would have them to go hunting if I needed them. Never actually shot them, but I recently got a chronograph (the basic Magnetospeed) and decided to test them out to see what kinds of speeds I could get. My loads were as follows:

123 gr. A-MAX in Hornady Brass
2.245 COL
25.3 gr. Hogdon H335
WSR primer

According to my reloading manual, this same load produced 2200 FPS in the 18" 1x8 twist AA barrel. My SS BHW barrel has the same specs, so I had assumed they would be pretty close to each other. My loads, however, were averaging 2090 FPS, 110 FPS slower than the AA barrel. Is this normal?

SIDE QUESTION

Because I hate making new threads: How's the ELD-M for hunting? Has anyone used it? Purposes would be hogs and white tail.

[LRRPF52]

What temperature were you shooting in?

[Slinkz]

Just below freezing if I remember correctly

[LRRPF52]

Just below freezing if I remember correctly

There's your answer. Ball powder in cold temps like that = significant combustion reduction.

Electron flow is not as fast in those temps, so the chain reaction of igniting the powder column is much slower.

[Slinkz]

Hm. I didn't realize that temperature could cause that much of a change. Sounds like I've got some reading to do. Thank you for your help.

[LRRPF52]

Extruded powders tend to be less sensitive to temperature shift.

[Slinkz]

Thank you. I'll have to do some more research before I make my next powder purchase. I just kind of grabbed the first thing that I saw that was in my handbook (hence picking the powder with the smallest max speed available). Again, I appreciate the help and advice.

[Commander184]

Were you at the same range? Temp, humidity, barametric pressure, and more contribute to a change in velocity. Yesterday's data will be different than today's.

Try imr 8208 xbr it did well for me around 10 degrees F. I've only been using it This winter, and I'm happy with my velocities. Your coal seems short too. Go out to 2.260 and you will be safely under the max. I'm running a coal of 2.270 as a test. Amax 123 never had a problem with 2.265 and barley up

[LRRPF52]

Humidity and barometric pressure have nothing to do with muzzle velocity. Humidity and pressure can't affect the internal ballistics measurably.

Only temperature will affect it. If you had the same temp on the moon, you would have the same mv.

You will see barometric pressure especially, and humidity to a very small degree affect retained speed as the distance gets beyond the muzzle.

Humidity is such a small factor, that if you change your values from 0% to 100%, you might see .1 mil of drop change at 1000yds, and you will never see those kinds of humidity changes on earth.

Most long range shooters just set humidity to 50% in our programs and don't look at it much, unless shooting for 1st round connect at ELR well beyond 1000yds.

[LR1955]

Hm. I didn't realize that temperature could cause that much of a change. Sounds like I've got some reading to do. Thank you for your help.

Slinkz:

Let me understand the question. You are comparing real loads shot over your Magnetospeed to published data from Alexander? I believe that is what you said.

And the air temp was around freezing.

I will disagree with my friend LR52 about an air temp of about 30F making a 110 fps difference from an air temp of 70F (which is what most ballistic tables use for a standard). Something I have noted about commercial and military powders is that they are pretty efficient from about 10F to about 130F. I place no bets on anything below zero or above about 120 or 130. This means powder temperature for internal ballistics, not air density related to air temperature.

Why the difference between AA published data and your real data? Could be a number of things. Here are a few. Your barrel is probably made a bit differently than the test barrel AA used. Your H-335 could be a different lot of powder than the one AA used. AA normally uses CCI-450 Small Rifle Magnum primers. You used WSR. Your Magnetospeed chronograph may not be as precise as the chronographs AA is using. Chronographs are good tools but take their readings with an understanding that they are probably high or low for what ever reason they have to be high or low.

Sure, ammo temp did something but it didn't cause more than five or ten fps of the 110 fps, if that much.

LR55

[LRRPF52]

There's a chart with most of the rifle powders that was on Hodgdon's site, but it has since been taken down.

Some of the powders were well over 1.5fps per degree Fahrenheit change.

So if the baseline was 70 degrees, and he's now shooting in 30 degrees, that's a 40 degree change.

40 x 1.5 = 60 fps change

Found it:

HS-6 1.21fps per *
H110/W296 1.24 fps per *
Imr4227 1.17fps per *
Lil' Gun 1.31 fps per *
RL10x .71 fps per*
Benchmark .44 fps per *
Imr3031 .73 fps per *
Imr8208xbr .59 fps per *
H4895 .23 fps per *
Alliant Varmint pro .89 fps per *
Alliant AR comp .77 fps per *
Varget .19 fps per *
W748 1.32 fps per *
Imr4064 .53 fps per *
Ramshot Tac .91 fps per *
Imr4895 .87 fps per *
AA4064 1.11 fps per *
AA2520 .98 fps per *
RL15 1.52 fps per * from 50* and up
PP2000MR .99 fps per *
Imr4320 1.32 fps per *
Ramshot Biggame .98 fps per *
H380 1.44 fps per *
VV N150 1.08 fps per *
H414/W760 1.42 fps per *
Imr4350 .64 fps per *
AA4350 .47 fps per *
H4350 .29 fps per *
RL17 1.42 fps per *
Hybrid 100v .78 fps per *
RL19 1.61 fps per *
VV N160 1.24 fps per *
Imr4831 1.19 fps per *
Ramshot Hunter .86 fps per *
H4831 .36 fps per *
RL22 1.71 fps per *
Imr7828 1.36 fps per *
Magpro 1.01 fps per *
H1000 .21 fps per *
RL25 1.59 fps per *
Ramshot Magnum .87 fps per *
Retumbo .49 fps per *
RL33, still trying to get my data for this one.
US869 1.68 fps per *
H50bmg 1.64 fps per *

[LRRPF52]

Another thing I noticed is that you have a BHW barrel, which has more shallow rifling.

This will build pressure differently, with less resistance to an Enfield conventional rifling profile, resulting in lower pressures and less speed with the same load, all other things equal.

[Commander184]

Good to know. I guess I am splitting hairs, at 1250 yards i figured every bit of correct data was worth my time.

[LR1955]

There's a chart with most of the rifle powders that was on Hodgdon's site, but it has since been taken down.

Some of the powders were well over 1.5fps per degree Fahrenheit change.

So if the baseline was 70 degrees, and he's now shooting in 30 degrees, that's a 40 degree change.

40 x 1.5 = 60 fps change

Found it:

HS-6 1.21fps per *
H110/W296 1.24 fps per *
Imr4227 1.17fps per *
Lil' Gun 1.31 fps per *
RL10x .71 fps per*
Benchmark .44 fps per *
Imr3031 .73 fps per *
Imr8208xbr .59 fps per *
H4895 .23 fps per *
Alliant Varmint pro .89 fps per *
Alliant AR comp .77 fps per *
Varget .19 fps per *
W748 1.32 fps per *
Imr4064 .53 fps per *
Ramshot Tac .91 fps per *
Imr4895 .87 fps per *
AA4064 1.11 fps per *
AA2520 .98 fps per *
RL15 1.52 fps per * from 50* and up
PP2000MR .99 fps per *
Imr4320 1.32 fps per *
Ramshot Biggame .98 fps per *
H380 1.44 fps per *
VV N150 1.08 fps per *
H414/W760 1.42 fps per *
Imr4350 .64 fps per *
AA4350 .47 fps per *
H4350 .29 fps per *
RL17 1.42 fps per *
Hybrid 100v .78 fps per *
RL19 1.61 fps per *
VV N160 1.24 fps per *
Imr4831 1.19 fps per *
Ramshot Hunter .86 fps per *
H4831 .36 fps per *
RL22 1.71 fps per *
Imr7828 1.36 fps per *
Magpro 1.01 fps per *
H1000 .21 fps per *
RL25 1.59 fps per *
Ramshot Magnum .87 fps per *
Retumbo .49 fps per *
RL33, still trying to get my data for this one.
US869 1.68 fps per *
H50bmg 1.64 fps per *

LR52

Although only using a chronograph, MRE heaters, and a ice box of ice, I came to the conclusion that the velocity changes are non linear. They don't do much unless you stray a good twenty or so degrees from 70 either way. Found cold to have more effect than hot.

And that it is hard to measure powder temp unless it has been sitting outside in very cold or very hot conditions for a few hours. And that a hot chamber will warm the ammo up pretty fast. Or the ammo sitting in the sun, solar loading, even in very cold conditions.

His change was 110 fps. What about the other 50 fps?

And finally -- I am not in any way looking for an argument. Yes, as powder temp changes, so goes velocity. And yes, the average of about 1.5 fps per degree of change in ammo temp is what I would use if I had nothing else and really needed it. And I doubt I would really need it unless I was forced to take a shot at serious distance without having the benefit of any sort of zero in those conditions. Up or down a half minute at 600 and maybe a minute at 1000 is better than doing nothing if the temps are pretty extreme.

LR55

[LRRPF52]

I think it's a combo of the temp and shallow rifling.

AA barrels often produce faster speeds than average for some reason as well.

Stokes said when they chrono'd barrels produced consecutively for high power, he saw 100fps spread across them out of the same manufacturer, same run.