Powder and primer accuracy? How does it work

[tuffbuff]

New to reloading and trying to understand a couple concepts on this effecting accuracy. Got basically 4 parts case,bullet,powder and primers.

I get the case prep stuff the common stuff makes sense and the bullet seating depths. Just trying to figure out how the different powders and primers effect accuracy especially 2 that are close in burn rate like h1000 and R22 and cci and fed primers. Any theory's or facts out there, just trying to save myself some time working up loads possibly.

I have one rifle that seems good, and another one I think should be better.

Also how much H4831 can you fit in a 7mag case

Thanks!

 

[ultimate_monkey]

pretty much burn rates and consistancy

for powder "pretty close" can be a difference of a few thousand (or more) PSI , and that is no where near close . depending on how long and high that peak pressure is, its worlds apart, especially at long range

primers, is how "hot" do they burn and how consistent are they in that brand / lot

 

[rokoro]

New to reloading and trying to understand a couple concepts on this effecting accuracy. Got basically 4 parts case,bullet,powder and primers.

I get the case prep stuff the common stuff makes sense and the bullet seating depths. Just trying to figure out how the different powders and primers effect accuracy especially 2 that are close in burn rate like h1000 and R22 and cci and fed primers. Any theory's or facts out there, just trying to save myself some time working up loads possibly.

I have one rifle that seems good, and another one I think should be better.

Also how much H4831 can you fit in a 7mag case

Thanks!

Tuff Some rifles seem to be a little fussy. However there are some things you can do to help with consistency. Primers can make quite a difference in my experience. For large belted cases with 75 grs of powder or more you need a good HOT primer for consistant ignition. I like the Fed 215 primer for large cases. For slightly smaller cases (like the 7mm Rem I like the CCI 250 primer. It is a mag primer but not quite as hot as the Fed 215. For standard 06 type cases and smaller I like the Winchester WLR primer. Whatever primer you use one of the most important things is how it is seated. A primer should be seated FIRMLY in the bottom of the primer pocket. I use nothing but a hand priming tool for this. You can "feel" the primer being seated to the bottom of the pocket. Another thing that helps with consistency is the powder you use. I prefer to use a powder that just about fills the case with the bullet seated. I don't like heavily compressed loads, just full cases. You mentioned the 7mm Rem and H4831.What weight of bullet are you shooting with that powder?? If you are shooting light 7mm bullets (in the 120 to 140 gr range) a slightly faster powder like IMR 4350 may give you more consistant accuracy. H4831 would be the slowest powder I would use with lighter bullets in the 7mm rem. If you are using heavier bullets say in the 160 to 175 gr range a slightly slower powder may be better. Something like IMR 7828 would be my first choice. Some rifles shoot just about any combination well ,while others can be fussy. Hope this helps

 

[Boomer]

If you talk to match shooters, they'll tell you the primers they prefer are the ones that produce the least amount of violence while still reliably igniting the powder charge. I prefer to err on the side of hot primers, and use magnums for all but loads in my target rifles, and my stuff seems to shoot straight. CCI primers are my preference, they fit the primer pockets a bit tighter, and you might get an extra firing or two out of a case before it has to be culled due to an expanded primer pocket.

The powder choice that produces the best accuracy is an interesting dilemma, and as soon as you discover one rule of thumb that sounds promising, like the powder that fills 95% of the case will be the most accurate, you'll come across a combination that contradicts it when a powder that only fills 70% out shoots it in your rifle. This might be expected if you were shooting light for caliber bullets, which generally do better with faster burning powders, which take up less powder volume by the time maximum pressure is realized. Notice the weasel words in that statement: could and generally; nothing is written in stone. Go figure. Then you have to choose between ball and extruded powder, and if extruded is your preference, then you have to choose between regular and short cut. If that isn't confusing enough, now there are high density extruded powders like H100V which produce the burning characteristics of extruded powders, put meter like ball powder. The best bet is to check your manual(s) to see which powder produces the best velocity for a given bullet weight, and start there, unless there is a specific velocity envelope you wish to hit, or unless you are heavily invested in one particular powder.

H-4831 in the 7 Magnum - I think you can expect maximum loads to be between 60 grs (175gr bullet) and 65 grs (150 gr bullet) with between 80% and 85% of the case capacity used.

 

[chrismc]

Only your rifle will tell you what it likes - the rest is hearsay...
Load the same loads with different primers - then go shooting, and compare! Your questions will be answered.
If you are new to this addiction you will soon learn what works in a particular rifle is something you have to find out by trial and error, very few like the same recipe.

 

[tuffbuff]

My dads 700BDL is being a sweetheart with my first ones I have RP cases at 2.493, Fed 215 match primers and 150 TSX's at 50 off lands with H4831.
Barnes says 62max and hodgdon says 68 max so I did 4ea at 60,61,62,63,64 and 65 and all under one inch but 2 that are over. No vertical but a bit of horizontal which I figure is me. Next ones loaded are 66-69 in .5 increments and I think my max is in this bunch and will load 1 grain under depending on accuracy.

My 260 shoots well with factory so I did some for it as well fed cases, cci Br2, h4350 and 130 accubonds at 30 off lands. I need to give this one a fair shake I guess as these were my first ones and was more worried about them going bang, they are mostly around 1.5"-2" for 3 shots I get 2 almost touching and one 2" off a fair bit, read that might be seating depth? I'm not at max yet at 43.5g. So this one needs to get played with.

Some guys say 1/2 inch with certain powder and the next guy says 4" etc with same stuff and also changing primers and shrinking groups a bit, just trying to figure er out. So i got burn rate and hotness of primers and technique seating so far, thanks!