doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com RST Patterns

I patterned a gun yesterday using RST's "2 1/2" loads (20 ga. 7/8oz 7.5s @ 1150 fps; despite the name, the case is 2.75"). They patterned significantly more open (65%) than I expected (80%). I obviously need to pattern some other loads for comparison to see if it is the load or the gun, but in the meantime I would be curious to hear if anyone has had a similar experience with this load.

Thanks in advance, Doverham

lower velocity loads with smaller shot, often pattern more open than do higher velocity loads with larger shot, regardless of the brand of the shell...

Not even close.

Shot size and velocity are TWO different variables.

In general, large shot shoots tighter than small shot.

In general, low velocity = tighter patterns. It's a shot deformation issue.

The biggest single variable is shot hardness, followed by shotcup effectiveness, followed by velocity. You need to investigate this for each shot size to have any meaningful data.

The single tightest shooting 20 gauge load I've seen was Federal 'Field and Range' circa late 90's in shot size #8. It turned any open choke gun into at least 70%, and maybe more. It was a fast load of #8, but the shot was exceedingly hard - harder than bagged STS shot or bagged West Coast shot. Man, it was hard.

Anybody have thoughts on RST shot hardness? I recall reading (Tom Roster in SSM, maybe) that B&P and Fiocchi VIP shot were harder than most commercial loads.

I remember talking to them at the vintagers one year, I believe they said they use Lawrence magnum shot. I remember reading an article somewhere that has lawrence rated towards the top in hardness.

I'm guessing this is going to be a gun issue, I've shot a lot of RST and found it to be top notch. The gun you patterned is probably more open than you think.

Or possibly more open than what I asked for when the fixed chokes were set. Obviously, some more patterning is in order before I reach that conclusion.

65% is awfully close to full choke.

That's tighter than I personally want a 20, but if you really want it to shoot even tighter you might try hand loads with some of that Italian nickel plated shot that BPI sells.

I'd try something like Herco, and a wad like the SP-20 that has a long shot cup.

Some guys say that the base pellet hardness is more important than the plating, but like most of this it's subject to debate.

Good luck.

What is the choke constriction measured with a bore micrometer?

Actually, I had specified 80% at 30 yards which is more like Mod. 65% at 30 yards would be closer to IC.

I understand that the issue with nickel plating is whether it is actually plated, or just washed - the latter apparently does not add much to the hardness. Thanks for the reloading tips, I may have to go down that path.

I have not had an opportunity to have the bore constriction measured, as I don't have a micrometer.

Ah, the old 30 yard trick.

I can vouch for the BPI nickel.

A one ounce load at 1125 fps I've worked up for a 12 gauge Parker with #5 BPI nickel turns the .008" choked right barrel into something north of a solid modified.

It's pricey, but I don't shoot much of it. Nice option though.