7MM Grand Slams

W

Wendyj

New member
I bought some pulled Grand slams from RMR at a pretty good deal. Mixed batch of 175 and 160 grain. These have the most variations in weight of any bullet I've ever bought. I have an old manual from Lyman and the cannilure is not even close to the bullet to set properly. 3.260 for 175 grain and 3.240 for 160 grain. Husband said he used to shoot these in factory and liked them. The 160 Speer hotcore has been a good bullet in the rifle so thought I would give these a try. Any idea of the seating length and the variation in weight. Been seating the hot cor at 3.290 and is extremely accurate with RL 22 but it doesn't have a cannilure to try and seat to.
 
I think (emphasis on think) that the 7mm Grand Slams were designed for use in the 7x57 which had a very generous throat for an older 175gr round nose bullet.

Just seat them to your load and ignore the crimp groove.

Jimro
 
You don't have to seat to the cannelure, but you can. That works fine in my 308 with the 165 GS.
 
I have lost faith in Grand Slams, based on admittedly little experience. I shot two elk with the 175 grain 7mm mag. At least both elk were killed. However the first was hit in the spine from about 40 yards and failed to expand at all. Just the point was flattened. The second was hit at about 200 yards and penetrated to the opposite shoulder where it came completely apart. Perhaps I got a bad batch, but that was total inconsistency. I went back to Nosler. Always good performance.
 
I shoot them a lot in 7mm Rem mag and they are very accurate in my Model 70. I developed my loadings from the old Speer manuals, and seated in the cannelure as directed. Never hunted with rifle all that much though. My friend borrowed it for a hog hunt, shot 200 pounder through both shoulders and it dropped. Never recovered bullet.

These have a flattened point to prevent bullet damage, so if you are looking at OAL data for a pointed bullet, it will be too long for a GS bullet.

Gun store had them on clearance and I just bought another 100.
 
Mine are flattened tips also. Rocky Mountain Reloading had 250 mixed 175 and 160 grain for $$60.00 about three weeks ago so I couldn't pass up a bargain. Weighing them I found about a 50-50 ratio of each. Husbands old Remington 700 loves the 160 Speer Hot Cors and thought these might work as well. They are both flat base bullets. I seat the hot Cors at 3.290. Actually all Noslers and Hornady or Sierra are all seated at that oal but the grand slam in my old manual shows seated deeper but still not enough to get to cannilure. Using Imr 4831 and Reloader 22. Reloader 22 better on bullets over 150 grain. In this rifle anyway. Wont get to the range for a few weeks but this rifle will group under a dime if I get everything right. Shame I can't shoot it. Recoil is a little much for me.
 
If seated deeper wouldn't I need to back off on powder charge. Just my thinking.
Click to expand...

Just my opinion but yes, especially since you're changing bullets. Start low and work up to be safe.
 
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