Been reloading for a while now ... finally bought a chrono and I seem to get one or two with a 80fps (fast) or so difference in speed between fastest and slowest. When doing load work up I def load all cartridges to same weight... using Lapua brass, cci primers and varget powder. Ive always seemed to get this even using federal brass which I mistakenly thought was my problem. Using Chrony master chronograph. Chrony is 10' from muzzle. Bullet most accurate so far is 168 smk averaging 2650 fps. Just looking for ideas on possible causes for such a spread. Oal is always 2.800. Gun is Rem 700 SPS tactical 1/12 twist 20"
- Thread starter abadrs
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Move the crono back a little. The next thing that may help is a little is neck, and primer pocket tune up. Also there are some primers that just work better with some powders. Varget lite with CCI 200's or BR-2's are a tried and true combo. I've found the softer I can reliably lite the powder the better the S/D an E/S will be. Also some bores that are still stripping copper will have misleading numbers. By that I mean do not crono until you have 20 or so down the tube because if the numbers get better w/ the same load over a clean bore you will be chasing what you think is a load problem when it's not.
HTH
HTH
OK, then try to even out your neck tension and uniform the primer pockets. The other thing I forgot to say is different lighting, on some crono's will move the numbers around as well.
What type of powder measurer are you using? Are you shooting shooting shooting ?? Or shoot and hold off for a minute or two. Also keeping rounds in a hot chamber will throw your velocity off in terms of Es. I've used the chrono your talking about and had best luck with it just at dawn and dusk.
How are you weighing the powder charge? Is all the brass from the same lot and fired the same number of times and sized the same? Are all of your primers from the same lot? How much do you crimp the bullet and how consistent is your crimp?
RCBS ChargeMaster 1500 Powder Scale Dispenser Combo 110 Volt I found some of my variation went away when I got one of these.
RCBS ChargeMaster 1500 Powder Scale Dispenser Combo 110 Volt I found some of my variation went away when I got one of these.
I have found the a similar problem with fps spread...it's not massive and its not on every shot, if I crono 10 rounds 2 may show a significant deviation, the others will all be within less 10fps of each other, barrel has
500 round down it, I neck turned all the cases, weighed them, trimmed them to length, use 175 Sierra Mk's and redding comp dies....the only thing I do that is causing me bait of concern is I weigh charges on a digi scale that
cost the equivalent of 30$ (I know I know).... so I was planning to replace with exactly what 'diverdon' said, charge master 1500. Is it as consistent as people seem to say? I think the powered charge could be the culprit for the OP and for me.
500 round down it, I neck turned all the cases, weighed them, trimmed them to length, use 175 Sierra Mk's and redding comp dies....the only thing I do that is causing me bait of concern is I weigh charges on a digi scale that
cost the equivalent of 30$ (I know I know).... so I was planning to replace with exactly what 'diverdon' said, charge master 1500. Is it as consistent as people seem to say? I think the powered charge could be the culprit for the OP and for me.
Powder scales can build up a static charge and the weights shown can be off by .3-5/10 grain.
Do a Search on it, much info out there.
Do a Search on it, much info out there.
This is likely a big part of the problem. Fire form the brass, resize, and try it again. Contrary to what one would think, new brass is not consistently sized. And, even Lapua benefits from neck turning if you really want low e.s., and annealing between reloadings or at least every two or three.
As stated, if low e.s. is all you want to see, load and get that round down range. Don't even worry about aiming, just get it down range and through the chronograph before the cartridge heats up, and wait a minute or two between shots.
You should be able to get the Chrony out the standard 15' using the supplied cord.
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Not sure if you answered this or not, but how are you weighing your powder charges? If you are using a scale with a .1 gr resolution, you could be off a few kernels of powder and still have the same weight. Will that equate to a 80 ES, not likely, but pair that with slightly different case capacity, different case lengths etc, it all adds up. The closer to identical you can get everything the better off you are.
Ok I will fire form first and yes using powder thrower and beam scale. I did look at past chrino speeds using federal brass and was getting about 40 fps in 10 shot average.. I thought it was as bad with the old federal brass I used but I guess I was wrong glad I wrote it down..lol
I'm probably going to get some flak on this, but here goes. What is the brand of your chronograph? If it's Chrony ...anything, borrow a decent chronograph. I've had 3 of them. Only good for paper weights and door stops.
I used to have an oehler 35P, I just don't get caught up on the numbers game anymore. Shoot for groups and do what your target is telling you, sure you want low ES and that will come with proper reloading. But I've seen my lowest ES shoot much bigger groups that ones I've found by looking at groups and target POI, even at distances.
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