Cast Boolit loads for HK SL7 or 770

[6string]

Hi,
Any of you guys ever work up cast boolit loads for the Heckler & Koch SL7 or 770, both in .308/7.62?
These are nice looking sporting/hunting rifles built on the roller block action more commonly used with the HK91 military style rifle.

A buddy of mine back in the 1980s had a H&K 91 that he upgraded with several G3 sniper rifle parts. He used it for 800 meter service rifle matches in Canada. He also worked out some cast boolit loads using the RCBS 165 gr Silhouette mold. He heat treated his cast bolts and his loads functioned reliably (thanks to the adjustable gas port) and were accurate out to 800 meters.
Anyhow, I thought I'd take a shot and see if anyone loaded for the rarer H&K hunting rifle based upon the HK91.

Thanks!

[Texas by God]

I would think that with the roller locked action, you will need to approximate military loads in velocity or use a heavier bullet for function. But, I'm just guessing here. One of my brothers had the H&K .308 SL7? It was a neat rifle.

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[Doughty]

I have one and found it relatively easy to work up loads for. I first used 3031 but 4895 also works. I believe many others would also. I used the Lyman 311014 bullet sized to .311. Early on I used AC WWs, GCs and lube. Lately it has been heat treated WWs, PC and GCs. I used book starting loads and worked my way up until my rifle found something it liked. I don't have my load data with me right now, but I believe the velocity was around 2300 fps on the last loads. Didn't have a chrono back in the 80s when I first started with it, but the first loads poked holes through 1/4 inch steel at 50 yards.

[6string]

Hi,
Thanks for the replies. Doughty, your experiences are much in line with my friend's experience all those years ago. I don't recall that the polygonal barrel was problematic. Overall, it's curious that these have fallen by the wayside. They seem pretty slick and filled a niche that has not readily been filled.

[Doughty]

Looking at some old load data. 40 grains of AA2520 also worked well with the Lyman 311041, GCed, sized to .310 out of lino. Same bullet without the gas check and 35 grains was okay but not great.

The SL 7 is a little heavy and the safety location is not the best, but if I had to go somewhere where there might be a very serious, no excuses, need to kill something, the SL 7 loaded with jacketed 150s is what I would take.

[Tim357]

A little off topic, but I sure wish now that I had purchased an SL7 whilst I was stationed in Germany...

[wyowillys46]

H&K roller locked rifles don't have gas ports. One can "tune" the rifle to a certain degree by changing locking pieces, but it's not something normally done.

[6string]

H&K roller locked rifles don't have gas ports. One can "tune" the rifle to a certain degree by changing locking pieces, but it's not something normally done.

Thanks for that correction.
Somehow, I thought my buddy had told me he'd made some sort of adjustment to account for the type of loads he liked.