I was able to extend my long-time love of Ruger firearms this past weekend by acquiring a GP100 stainless steel revolver with a 4" barrel. Based on its serial number I estimate it was manufactured late 1991.

I ran a box of Magtech .38 caliber 158gr LRN and a few cylinders of Independence .357 magnum 158gr JSP. The Independence cartridges used CCI primers (which detail will become apparent soon).

This revolver had been given a trigger job and it felt and shot sweet using the Magtech .38 rounds. When I started shooting the .357 there were two instances (in about half a box) where the primer was only barely dimpled, and when I repositioned the cylinder and tried again, they fired. Even when they had successfully fired, the dimple in the primer was still a little shallow. When I compared the fired Magtechs and Independence brass, the Magtechs were all consistent in dimple size and depth but there was a fair amont of variability with the CCI-primed Independence brass. CCI has a reputation for hardness, and I suspect that the trigger job was optimized for target ammunition with softer primers.

I think I will see about installing a little stiffer mainspring. The spring kits are cheap, and the instructions are pretty straightforward. I plan on feeding my GP100 a lot of wadcutter handloads so I'll have a bit of control as to individual components, but I feel I need to at least ensure that any ammunition will fire consistently.

Congrats on the GP100 denis. Ruger DAs are hell for strong and always seem to deliver good accuracy. You bring up a good point about the trigger and light primer strikes.

Far too often lighter mainsprings are chosen as a less expensive way to get a lighter trigger pull. Good trigger jobs take patience and a little time to perform. OTOH, my opinion is that some trigger pulls can be far too light if the firearm is used for PD or hunting. While we each have our preferences, I like my working revolvers no lighter than 4lbs.

Denis, I watched my buddy shoot a 0.75" group with his 6" GP-100 at 25 yards, off a rest. If he'll give me the load I'll pass it on. If he won't I'll steal it from him next time we go to the range...

Handloader wrote:

Far too often lighter mainsprings are chosen as a less expensive way to get a lighter trigger pull. Good trigger jobs take patience and a little time to perform. OTOH, my opinion is that some trigger pulls can be far too light if the firearm is used for PD or hunting. While we each have our preferences, I like my working revolvers no lighter than 4lbs.

Fortunately this trigger job was a little more involved than changing out the mainspring.

One of the benefits to living in Columbia MO is that I can go onto the MidwayUSA web site, place an order, and pick it up 3 hours later at the loading dock. So I ordered the Wilson Combat Custom-tune spring set which allowed me to put in a somewhat stiffer mainspring.

This'll give me the peace of mind knowing that even CCI primers will fire consistently. The trigger still feels smooth for the entire pull, which is still far better than I enjoyed 30 years ago with my S&W Model 19.

Pumpkinslinger wrote:

Denis, I watched my buddy shoot a 0.75" group with his 6" GP-100 at 25 yards, off a rest. If he'll give me the load I'll pass it on. If he won't I'll steal it from him next time we go to the range...

That's not bad! I look forward to hearing what his load was.

denis,

I recently sold mine (it had a 6" barrel) and, even though I received good $ for it, I still regret doing it.

OK so it seeems like a lot of us like Rugers myself included. My GP-100 is great, all my M77's are great,single six,vaquero,markII and I just got a new SP101 in the .327. Being a bit older, ahem, I now realize there is a proper break-in procedure for new firearms. NOT to start any bashing on how-to's, what have you all found in your experience to properly "season" a new Ruger?

Brewmaster, to be honest I clean the bore once before I try it and then just shoot 'em and clean 'em.

That is what I have done in the past and it seems to work out great. Guess that is what I will keep on doing. Thanlk you for the input..

Pumpkinslinger wrote:

Brewmaster, to be honest I clean the bore once before I try it and then just shoot 'em and clean 'em.

That's what I do, especially with my handguns - I don't have the patience to be anal about it. For my long guns I fire 5, run a boresnake 3 times, fire 5, boresnake 3, fire 10, boresnake 3, and call it good. Might upset some people, but they don't have to shoot my guns.