Whether I use QuiclLOAD or data from Hodgdon's published measurements, going from 48.5 grains of IMR 4064 to 49.5 grains (a 1.0-grain span or ±0.5 grains), I get a 46 fps velocity difference. With the 150-grain Hornady FMJ, at 200 yards the total drop difference is 0.3 inches. So, by itself, that isn't enough to matter. What will matter is whether your barrel times change the angle of departure enough to see the difference at 200. The odds are good they won't be. However, if you shoot a ladder to see that you are in the middle of a deadspot in muzzle rise or fall with your center load value, that is what will offer the most immunity to charge error at that range. It won't be that 46 fps number unless your SD is zero. It will be more like the 46 fps addition plus your highest extreme spread number at 49.5 grains verses not having the added 46 fps and the lowest extreme spread number. If you suppose that takes you across about 100 fps of velocity range, you have more like a 0.8" drop difference. Still pretty hard to see with a service rifle target.
IMR 4064 vs IMR 4895 metering?
- Thread starter BobCat45
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I don't understand what you said there . As I read it you say two different things . 1gr only has a 46fps difference and .5gr has a 46fps difference . As someone that has chronoed many hundreds of rounds using IMR 4064 in a 308 shooting 168 through 200gr . Working up in .5gr increments . Your .5gr increment producing 46fps difference from the the last and the next is spot on . which also means 1gr difference is likely 92fps . Your ES will be that and that's going to be the best it can likely be .
That's what I've seen using 4064 through a chrono and is why I find my .4gr +/- throws unacceptable . My avg is more like +/- .25 but I've never thrown 15 times or so and didn't see that +/- .4gr come up . Obviously my Hornady powder measure is not as good as some others which I'm starting to see with most Hornady products . Good and in some cases pretty good but rarely top shelf products .
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The Hodgdon data for a 150-grain Nosler Ballistic Tip has 47 grains producing 2743 fps and 51 grains producing 2928 fps. The difference is 185 fps. When when you divide that by the 4-grain difference in start to max charge, you get 46.25 fps/grain. So I'd meant for the whole grain to produce a 46 fps difference and 0.8" drop difference. But in real guns, you get those velocity rises and flat spots that don't appear in computer simulations, nor do you know if it messed with the fps/grain figure of the Hodgdon data. The drop is from a ballistics program that gives you a difference for a perfectly rigid gun that doesn't have muzzle rise or deflections due to recoil moments or the effects of the shooter's position and solidity. So, with none of that taken into account, what you are seeing (and, in someone else's chamber, possibly the opposite) can happen despite Hodgdon's numbers. The bottom line is that it is in the noise of most folks shooting service rifle at 200.
If I use Hodgdon's data as valid for test barrels, the military velocity for the 152-0.3 grain (150.5-grain average) M2 bullet would read 2790 fps at 15 ft from the muzzle (where Hodgdon will have measured it) and will read 2740 fps at 78 ft from the muzzle as traditionally measured by the military (an average velocity between 2 and 52 yards, or at 78 feet). So their test barrel, if there were no velocity flat spots or rises, would hit that military velocity number right at 48.0 grains of 4064 using their component combination. So that should mimic a military load fairly closely.
In a Garand, the velocity won't match Hodgdon's or the military's test barrels. What I have done in the past is match Hodgdon's load and components and get a velocity from my gun, in position, then switch to LC brass and the #34 primer and the Hornady or Sierra FMJ bullet and check that no major change occurred. Assuming not, that's my starting point from which I look for the best accuracy charge by laddering a grain and a half in both directions.
If I use Hodgdon's data as valid for test barrels, the military velocity for the 152-0.3 grain (150.5-grain average) M2 bullet would read 2790 fps at 15 ft from the muzzle (where Hodgdon will have measured it) and will read 2740 fps at 78 ft from the muzzle as traditionally measured by the military (an average velocity between 2 and 52 yards, or at 78 feet). So their test barrel, if there were no velocity flat spots or rises, would hit that military velocity number right at 48.0 grains of 4064 using their component combination. So that should mimic a military load fairly closely.
In a Garand, the velocity won't match Hodgdon's or the military's test barrels. What I have done in the past is match Hodgdon's load and components and get a velocity from my gun, in position, then switch to LC brass and the #34 primer and the Hornady or Sierra FMJ bullet and check that no major change occurred. Assuming not, that's my starting point from which I look for the best accuracy charge by laddering a grain and a half in both directions.
In my test .5gr regularly produced a 40fps increase in velocity at each increment . I’d need to go back and look but if I recall I was surprised how consistent that was even with different powders of the same burn rate . They may not have been the same velvet cities but the incremental velocity increases were very similar.
I’ll go take a look at my logs and see if I’m remembering all this correctly . Boy would I feel silly if those consistent increments are actually 20fps :-(
I’ll go take a look at my logs and see if I’m remembering all this correctly . Boy would I feel silly if those consistent increments are actually 20fps :-(
Ok , the data I have/used was from 2013/early 2014 which was just before I changed my hold on the rifle helping reduce my ES/SD . Many of the ES's in the data I just looked at were in the 40's and low 50's which I believe screws with my results as far as the most recent topic about increments of velocity per 1gr and .5gr charges .
All my data was using 4064 going up in charge by .5gr increments shooting 175gr smk . I'll add I looked at 4 different load developments with the only difference being cases used or charge weights . Most were 41gr though 43gr but one was 38gr through 41gr .
I'm not going to write all the numbers down but will if asked . I'm basing this off my 5 shot avg's , it looks to me I generally was averaging around the mid 30fps difference from charge to charge . there were a few in the 50's and a couple in the 20's .
Based on my ES's my data leads me to believe Unclenicks data is likely more correct then what I remembered .
All my data was using 4064 going up in charge by .5gr increments shooting 175gr smk . I'll add I looked at 4 different load developments with the only difference being cases used or charge weights . Most were 41gr though 43gr but one was 38gr through 41gr .
I'm not going to write all the numbers down but will if asked . I'm basing this off my 5 shot avg's , it looks to me I generally was averaging around the mid 30fps difference from charge to charge . there were a few in the 50's and a couple in the 20's .
Based on my ES's my data leads me to believe Unclenicks data is likely more correct then what I remembered .
jetinteriorguy
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Basically +.5gr and -.5gr add up to a total possible variation of 1gr.
Haha yes , my concern was the 46fps every 1gr was actually only half of what my test showed for 1 full grain . Because of my ES’s being so high , I feel I have no choice but to defer to the experts . I’m still skeptical that every .5gr the velocity only goes up 23fps-ish but have no conclusive data to say otherwise . I mean if I were to pull out all my notes from the last 10 years I might find something that supports my memory but I don't care enough to do that lol .
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Just to close the loop; my original question is answered.
4064 behaves exactly like 4895 in my powder measures.
My friend did indeed have the IMR4064. I got it from him today, and tried it in the RCBS Uniflow and the Lee Perfect powder measures.
4064 was not happy in the Uniflow; it wanted to jam and cut, same as 4895.
In the Lee Perfect, 4064 metered evenly and without binding or seeming to cut, just like the 4895 did.
Threw ten trows in a beaker, weighed it, then threw ten individual throws weighing each one. All were within 0.2 grains of the average-of-ten and the extreme spread was about 0.3 grains.
Not enough measurements for statistics but it demonstrated to me that 4064 works as well in the Lee measure as 4895 does, which is all I wanted to know.
I haven't loaded or shot any yet. Need to prep some brass.
4064 behaves exactly like 4895 in my powder measures.
My friend did indeed have the IMR4064. I got it from him today, and tried it in the RCBS Uniflow and the Lee Perfect powder measures.
4064 was not happy in the Uniflow; it wanted to jam and cut, same as 4895.
In the Lee Perfect, 4064 metered evenly and without binding or seeming to cut, just like the 4895 did.
Threw ten trows in a beaker, weighed it, then threw ten individual throws weighing each one. All were within 0.2 grains of the average-of-ten and the extreme spread was about 0.3 grains.
Not enough measurements for statistics but it demonstrated to me that 4064 works as well in the Lee measure as 4895 does, which is all I wanted to know.
I haven't loaded or shot any yet. Need to prep some brass.
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