I'd like the benefit of YOUR experience with IMR 7828

[gerry]

I have used it in my 264 WM with good results, the gun liked Retumbo better though. In the 6.5x55 and 260 Rem IMR 7828 ssc works very well with 140's and heavier bullets from my experience.

 

[Oldtrader3]

I used 58.0 grains of IMR 7828 SSC in my .280 Rem and 160 Accubonds with W-W brass. Velocity was nearly 3000 fps and accuracy was great, <MOA.

 

[Jimbeaux82]

That is amazing. I can barely get 3000 fps out of my 7mm Wea Mag with a 160 gr AB.

 

[Oldtrader3]

I don't either, with 66.0 grains of IMR 7828 and a 168 grain LRAB I get 2930 fps. I t is crazy. Maybe my chrono has flipped?

Sorry, typo. I have been shooting the 7mm Mag since 1963 and am reaching the point where I would like to rebarrel mine into something useful, like a .280 Rem. I have never been able to tell any difference in performance between my .280 and the 7mm Rem Mag, except burning more powder and having more recoil.

 

[SJB358]

That is amazing. I can barely get 3000 fps out of my 7mm Wea Mag with a 160 gr AB.

That does seem a little odd Jim, as I would think you could get an easy 3050-3100 out of your 7mm Wby without really leaning on it PSI wise. Does it fall off as far as accuracy above 3K or just hit the PSI wall?

 

[Jimbeaux82]

I have not tried IMR 7828 with the 160 gr AB, but with other similar powders like RL22 , I seem to get worse groups at over 3000 fps and start getting pressure signs. I am able to get 162 gr SST's up to about 3100 fps, but not 160 AB's

 

[SJB358]

Jim, have you tried RL25 at all? That may be the one that lets your 7 Wby get up over. Even still, seems odd your 7 Wby starts getting psi signs around 3k. Is it a standard Wby chamber with freebore and 26" barrel?

 

[Jimbeaux82]

It WAS a standard MK V with 24" barrel. But I just sent it back to Weatherby Custom shop to retro fit it to an Accumark, same caliber. I did try RL 25 in my old rifle with 162 gr SST's. I got 2980 fps with 73 grs, same with 74 grs, same with 75 grs (which is the listed maximum by Alliant and several other manuals) but actually blew the case with a crack right above the belt. So I will take the velocity plateau along with blown case as a clear sign that I had reached my maximum velocity and pressure with this combo. I do plan to try RL 25 again once I get my Accumark back and maybe with the 26" barrel I will be able to do a little better than before.

 

[Oldtrader3]

It sounds more like a head space problem, if your case is cracking in front of the belt?

 

[Jimbeaux82]

It is the only time that has ever happened.

 

[jmad_81]

I have had great luck with it in my 280 AI, 6.5 SAUM, 243 when I had it, 270 Weatherby, and in my 338 RUM.

My favorite thing about 7828 is that I seem to always be able to find it.