Shot my 4" barreled stainless 357 mag Ruger GP100 a bit this past month, with some decent results. Also had some surprises. The home made~ 160 grain cast bullets, wheel weights, shot ok, (Lyman 357446), less than 3 inch groups at 25 yards.

When I shot some 170 grain cast bullets, I got some wide flyers. Some shots were out 6 inches from group at 25 yards.

Turned out the lighter bullets were sized closer to .356-.357." The 170 grain Keith bullets were a full .358". I measured the cylinder throats, and got readings of .355-.356" tighter than I expected.

I sent the cylinder out to have the throats reamed open to 0.358 (http://www.cylindersmith.com/). Just got it back, and hope to shoot it this week. True to form, the throats are now a uniform 0.358."

I had this work done to my Ruger 41 mag Bisley blackhawk, and it uniformed groups and elimiated odd flyers. The pistol is now an honest 1.5" grouper at 25 yards, and sub 4" at 50 yards (more like 3.5").

Hope the GP100 responds the same way. I don't understand why Ruger reams the throats at 0.355". I'm not shooting a 9mm. It's a 357 mag, If they can set a diameter to 0.355 (wrong) why can they set it "right" at 0.358"??

Anyone else use the services from http://www.cylindersmith.com/?

Service was $37, including return shipping. Work is excellent, with fast turn around time (inside 2 weeks from ship out to receiving it back).

Will post shotting results hopefully this week.

I for one will be eager to see the results... I have had extremely good luck with a 180-grain Truncated cone cast bullet out of my .357 Redhawk. I won't quote powder charge because it is WAY over the top, but the load was one ragged hole at 50 yards...

I'm picking up my new GP-100 3' stainless tonight.

It'll be my first Ruger handgun.

Interested in your findings.

Did some shooting today with my newly throated Ruger GP100 (4" stainless model).

Initial result appear positive. Before the throating on the cylinder, at 25 yards, my groups ran 3 inches or less, with an occasional flyer. At 50 yards, depending on the cast bullet, I had more of a pattern, than a group.

After the thoating (opened up from 0.355 to 0.358"), the 170 grain Keith load I was using (9 grains Blue dot, in a 357 mag case)) had 25 yard groups under 2", with 5 shots in ~ 1.5 inches. So, initially (and it IS early in the evaluation process) it looks like I shaved an inch off the group at 25 yards with this load.


At 50 yards, the 170 grain Keith bullet (same load) would print about a 5 inch group. Didn't see any flyers with the load, after the throating job.

I have some jacketed bullets on order. Also need to try some other loads (powders: Unique, 2400, and more blue dot with other bullets).

I would say (again early) that the throating job has made a positive improvement in accuracy. It's been money well spent.

I certainly need to practice more at 50 yards. I am using a bead front site, and a V rear site. I'm shooting a two hand hold with arms supported over the roof of my car in a local gravel pit. Not machine rested.

I have Pachmayer "gripper grips" on the gun. They have a slimmer, less bulky feel, but I wonder if the smaller grips may be an issue for a solid hold. I put the factory Ruger rubber grips (with wood insert panels) back on, and will evaluate to see if that makes a difference.

With a 4" barrel, and short sighting radius, there isn't much room for error for sight alignment. Mistakes are magified, which hurt accuracy in a hurry. Shooting technique has as much, if not more of an impact than "the perfect load."

I'm not unhappy with the 50 yard groups for now. I'm glad the wild flyers are gone. I know I wasn't THAT poor of a shot. Often you can "call a shot" and know it was "you." The flyers were a surprise-shich lead me to measure the throats.

I would like to see if different loads and/or just more practice will get the groups down to under 4" at 50 yards. If so, I will move back to 75 yards. In my thinking, 75 yards is the longest shot I would take at a deer with this pistol. I'd like to keep at least a 6" group from that distance from a field position (likely to be sitting down, with my back against the car/tree, two hand hold over my knees.) I haven't shot that way yet in these early shooting sessions-so it't another variable to anticipate providing an accuracy challenge. I'm up for the challenge. I'm having fun.

My 4" Ruger GP100 isn't really a "hunting gun" per se. If so, I would've picked up the 6" version. I wanted a "put it on your belt for a walk" gun, but want to see what it would do IF I had a chance at a game shot out to ~ 50-75 yards. It's a gun of opportunity, secondary to a rifle. Still, I want to be able to be proficient enough with it at 50+ yards in case I have the "opportunity."

I would like to work up a "squirrel" load for it. Maybe some wadcutters in a 38 special case for 25 yard shots.

It's fun to burn some powder after work to unwind. Haven't done that in a LOOOONG time.

Tarkus,

You may like this link for a good read on a 3" GP100.

http://www.thesixgunjournal.net/repatriatedrugergp.html

quote:

Originally posted by catboat:
Tarkus,

You may like this link for a good read on a 3" GP100.

http://www.thesixgunjournal.net/repatriatedrugergp.html

Thanks!

I bought and shot the 3" last night.

I left the range with a smile on my face.

This gun is a work-horse and I'm happy with it.

Now I need to work on my own 'mechanics'.

Shot the new GP100 again last night.

I'm trying to 'break-in' the trigger, so I'm shooting mostly double action.

While shooting the first 50 rounds of .38spl, the cycle became inconsistant.

It should have been a long draw to cock the hammer, but it took a bit more strength to initiate the pull.

While shooting .357 mags - the draw cycle was perfect.

The smith at my range figured two things:
1 - the action was getting some interference from the gunk - a quick oiling remedied this.
2 - the .357 explosion consistanly loosened any particles interfering with the draw.

It seems that the oiling - "out of the box" was insufficient after about 150 rounds.

I resumed and shot nice DAO groups out to 15 yards.

Can't wait till this breaks-in.