How much bullseye powder to cycle RO with slide mounted Red Dot?

I have a Springfield Range Officer.  It was purchased second hand off of Gunbroker.  I suspect it probably has the stock recoil spring (16 lbs).  I did change the mainspring to 19 lbs.  

I have been loading 4.16 grains of bullseye and shooting irons.  Right now I am on paternity leave, so I suspect that I will have more time to load than to shoot.  Will 4.16 grains cycle a slide mounted red dot, if I go that route?  Or should I hold off loading ammo?  I don't want to wind up with a ton of ammo that I can't shoot once I put a dot on my gun.

If I were you I would bench rest the gun at 50 yards and see if there is an accuracy difference between using the 19# mainspring and te factory mainspring. I did with mine. Gun came out of battery too fast and groups got bigger. 

I just got my Springfield back from John after having it rebarreled and a dot mounted on the slide. It shoots 4.0gr of Bullseye just fine. It stays in battery longer or unlocks slower than factory so it has a 10# recoil spring in it and a 19# mainspring as well. But the gun was rebuilt for such use. 

Your 4.18 load should cycle just fine even with a dot mounted. You may have to use a different recoil spring possibly but that's not a big deal.

I think your approach is a bit off.  Find the most accurate load for the gun and spring accordingly.  Not the other way around.

What bullet are you using for that load?

If the current load you are using is accurate with the gun, then it will still be accurate with a slide mounted dot on it.  Just go with a lighter recoil spring if needed.

Why did you change the mainspring?  I never did with my Range Officer.  Also be aware that changing your mainspring will affect your trigger weight.  2-3 ozs. per pound.

My RO with a slide mounted ultradot runs with 3.5 BE, 185 or 200 grain lead SWC, and a 10 pound recoil spring.

Please don't take this the wrong way, but unless you have the equipment and experience to effectively test for most accurate loads (takes many more than 10 with statistical tests), as a beginner (no classification) I would (and did) start with a universally successful load (say 3.8 - 4.0 B'eye or similar), load up 10 to 20 and try them.  If they are too weak to function, use the old fashioned technique of clipping a coil off the recoil spring.  Can be done at the range. A std. spring is ca. 16 lb, 32 coils. One coil removal represents a 3% reduction.  See what works.  Reduced coil springs work fine, and can be replaced with comparable commercial weights later.

Good luck!

Andy,

We are tuning Paul's gun right now.  I'm going to lend him a 12.5lb spring and see how it works with his new rail.  When we are done tuning his, we will have current springrate data.  I just don't remember what's in my gun.  I think it's a 12.

I assume the load the 4.16 load (you mush some powder drop) is good. Order a spring pack try the #10 first and go up until the gun does not cycle great. I use #11 with 3.8 BE under a 185 SWC. Key in my view is you want the strongest spring possible with the bullet that groups well.

I have the pro 1000 with the auto disk, so 4.16 is just what came out of my disk. The different mainspring was to reduce trigger weight.

That sounds good Rob, let me know what works with Paul's RO. I ordered the rib from marvel custom guns, I suspect it will take a couple weeks to arrive as the check went out in the mail today.