Vv n550

Bile

Bile

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Can anyone school me on this powder? Ive been playing with it a bit in my 308 ftr gun, and im seeing some good results so far. I snagged a few kgs last year during the panic, and this year i finally found a keg of imr i can use.

How sensitive is this N550 to temperature? For example, compared to imr 4064, imr 4895, varget.

Are there any specific primers which work better with this stuff? Ive been using fed gm210m primers and have been considering cci br2s.

I literally did not see any excessive pressure signs for my 175s at the max pressure on the reloading data. No flattened primers, no exessive cratering, or even a single extractor imprint. Is that normal?

thanks.
 
If you can find some Varget,stick with it and develope your load...Good stuff

My shooting Buddy loves VV and we have same results...I use Varget...
 
Unless you had your loads pressure-tested in a ballistic laboratory, you don't know if you've reached max pressure or not. You may be at max load according to the published data but that is only the max for the specific test rifle used to develop the data. I have various rifles that have pressure-issues before the max published load is reached (tight chambers and short throats) and other rifles that can hit max published loads and still not be up there yet (loose chambers, worn throats). Going by velocity is a better judge of how close you are to max pressure but even then that is just better, not perfect.

Check your velocity and compare it to the published velocity. This is assuming you have the same length barrel though. If the velocity is what it should be at max, I wouldn't go any further. If the velocity is still a tad low you can go above max little by little, if you want the extra velocity.

Different brands of primers will show "pressure signs" at different pressures. Federal primers will often start to flatten in 30-30 loads which max out at 42,000psi and totally flatten in higher pressure loads like 270 Win. CCI primers don't show much in terms of pressure until past around 60,000psi. A max load in a 308 usually wont do much in my experience to a CCI primer but it starts to show signs with a max load in, say, a 300WM. Cratering is most commonly caused by oversized firing pin holes in the bolt face but can be seen in softer primers (like Federal) without oversized holes. Brass is exactly the same; Federal brass can get loose primer pockets and show ejector pin marks at normal working pressures for a 308. Harder brass like military or Lapua wont show "pressure signs" until you are into dangerous pressures in a 308. If the brass is annealed and within the suitable hardness range for neck, shoulder, and body the cases will start to stick in the chamber (causing a stiff bolt lift) somewhere a little above 60,000psi. This is sure sign that you are playing with fire if it's a 308.
 
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All powders are temperature sensitive. Lapua uses N540 in their factory .308 155 grain match ammo, but N550 may be the ticket for heavier bullets if looking for top velocity.

Regards,

Peter
 
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