Finally found a good load for the 7mm WSM

[corbin9191]

Well I have been playing around with my 7mm WSM lately trying to find a good load with the 168 grain Target VLD's that my brother got me. I have been trying out H Retumbo, IMR 7828 SSC, Reloader 22, IMR 4350, and H 1000. I was having problems with my crony before by giving me false reading's by the crony not being fully extended (Just like everyone on here suggested), But I got that fixed by laying it on a flat surface and shooting a 22 through it, just to make sure that it was giving me the right readings. Well I loaded three rounds up of each powder and shot them through the crony. The H Retumbo gave me an average speed of 2985 fps, the IMR 7828 was giving me 3045 fps, the IMR 4350 gave me 3071 fps, Reloader 22 gave me 2935 fps, and the H 1000 gave me the best velocity with 3249 fps at 15 feet from the muzzle. This is all out of a 24 inch barrel and all the loads did not have a pressure sign on them. I worked up to 69 Grains of H 1000 and still no pressure signs. But with 3249 fps I was pretty impressed but thought the crony was still not fully extended so I went over and made sure that it was still fully extended and it was. So I shot another round through it and it gave me just 7 fps difference, but with all the rounds averaged it came to 3249 fps. Is this possible?

 

[DrMike]

Certainly, the higher velocity with H1000 is possible. However, if it is accurate it is indicative of higher pressure than is safe. The velocities you report with the other powders (Retumbo, IMR7828, IMR4350 and RL22) approximate what I would expect with a maximum or near-maximum load. What was the charge weight of the H1000 that generated the higher velocity?

 

[corbin9191]

Certainly, the higher velocity with H1000 is possible. However, if it is accurate it is indicative of higher pressure than is safe. The velocities you report with the other powders (Retumbo, IMR7828, IMR4350 and RL22) approximate what I would expect with a maximum or near-maximum load. What was the charge weight of the H1000 that generated the higher velocity?

It is 69 grains of powder

 

[DrMike]

Certainly, 69 grains of H1000 shouldn't be an excessive charge. There is the possibility that you have a "hot" lot of powder, showing normal variation in burn rate. The fact that your loads were within the normal velocity range anticipated with the other powders would indicate that this is at least a possibility, in which case you will want to be vigilant in watching for pressure. When you size the brass in preparation for the next loading, watch to see if the primers seat normally or if they are somewhat loose. Again, that velocity could indicate pressures in excess of a safe range.

 

[corbin9191]

Certainly, 69 grains of H1000 shouldn't be an excessive charge. There is the possibility that you have a "hot" lot of powder, showing normal variation in burn rate. The fact that your loads were within the normal velocity range anticipated with the other powders would indicate that this is at least a possibility, in which case you will want to be vigilant in watching for pressure. When you size the brass in preparation for the next loading, watch to see if the primers seat normally or if they are somewhat loose. Again, that velocity could indicate pressures in excess of a safe range.

Ok, I will keep a close eye on the pressure signs but so far there is none, but I will see about the primer pockets. The lot number of the powder is 1100909
4772

 

[JD338]

corbin9191

Keep in mind that loads developed in the cold weather may become high pressure loads when the temp goes up.

JD338

 

[DrMike]

Keep in mind that loads developed in the cold weather may become high pressure loads when the temp goes up.

Excellent advice that is too often overlooked.

 

[Jerry 919]

No truer words ever spoken than those of JD338.

When I moved to Oregon I started loading for .243 Win with 55 grain BT's and H414 powder. Killed alot of coyotes with speed right at 4100 FPS and .25" accuracy. This load was developed in the winter with temperatures in the 20's and 30's.

In August with the temperature at 85 degress I touched one off on a coyote. Man what a surprise. Felt wierd, sounded wierd and a thin wisp of smoke out of the action. Bolt difficult to open. Primer blown out of the pocket and welded to the bolt face. Casing removed with a cleaning rod.

Two fifty round boxes labeled. "Use caution--Winter Loads ONLY."

Whole lesson very scary.........and valuable.

Jerry 919
Bend, Oregon

 

[corbin9191]

Well I finally got the chance to check the velocity of the loads again. I found out that the battery was getting low so I replaced it then went to shooting. The load is only averaging around 2980 fps instead of the 3249. But the groups at 100 yards really surprised me, They are .463 inches 3 shot groups.

 

[JD338]

corbin9191

Sounds like a good load. This spring/summer, drop back a few grains and work up.

JD338

 

[DrMike]

The 7 WSM is one of my favourite cartridges. All that I have shot give me excellent accuracy. I'm not surprised in the least at your results.

 

[corbin9191]

The 7 WSM is one of my favourite cartridges. All that I have shot give me excellent accuracy. I'm not surprised in the least at your results.

If you don't mind me asking, what are your favorite loads for you 7mm wsm?

 

[DrMike]

My "go to" load is 160 AB charged with 69 grains of MagPro and WLRM. Sub-MOA groups and 2930 fps. I can get more velocity, but this is excellent accuracy. I have a really good load that I have not used, except to work it up, with 160 PT, 65.5 grains of IMR7828 and R 9.5M primers. Velocity is 2925 fps and groups are 0.3 inches.

 

[SJB358]

That 7WSM didn't get a fair shake. What a great round and alot of power in a nice, compact rifle. I would like a Winchester M70 FWT in one of those. It would be a heckuva nice hiking rifle. I like the 7mm Rem Mag, but the WSM's seem to really shine for their size. Scotty

 

[DrMike]

Scotty,

I like my 7mm RM; I love my 7mm WSM.