GP-100 and Boolits

[TCLouis]

How many rounds before my GP-100 settles down and starts shooting Boolits really well?

[Muddy Creek Sam]

Never Had a Problem with Boolits in our GP100. They were all loaded by GP100Man, Contact him for load data. Great Pard, Real knowledgable about Rugers.

Sam :-D

[GP100man]

TCLois
what `ca shootin in it???
alot of the late GPs cyls are a mite smaller than the bores, but they are spotty to where they show up at .
my 6" SS has never had a jacketed bullet fired in it since it left the factory.

GP100man :cbpour:

[Bret4207]

Kind of like asking, "What makes women happy?" Depends on the woman, I mean gun! Are you fitting your boolit to the gun or trying to get the gun to fit your boolit?

[Down South]

I’ve heard it said by some that sometimes it takes up to several thousand rounds. I’ve heard it said that jacketed bullets are best to break a barrel in. I couldn’t tell you for sure if either of those two statements will hold water or not. I have a SS GP-100 W/6” barrel and it does very well with cast but the cylinder throats have been reamed to a uniform .358”. I’m sizing a 358429 boolit to .359” (Beagled Mould). I’m getting good accuracy and no leading.

[catboat]

Measure the throat of each chamber (the opening of the cylinder where the bullet exits).

My 4" stainless gp100 had 4 throats ~ 0.355", and two around 0.356". My bullets were sized .358". They were being squeezed down to the smaller size, then entering the barrel. Not good. I was getting 4" groups at 25 yards.

I had my throats opened up to .358", and now that same load/bullet/sizing diameter prints sub 2" groups at 25 yards. It cost $40.

Don't get frustrated, and don't settle for poor groups. Measure your throats, and if they are tight, consider opening them up. I'm sure there are many different experts on this, who have done more testing than I, but after conducting an internet search on this, I found one common thought. The cast bullet should be the same size as the throat (should be able to gently push the bullet through the throats with your finger (throat doesn't change diameter). Then, that same bullet (no loaded cartridge) should enter the barrel's forcing cone by something in the area of ~ 1/2 bullet length.

It made a big difference to my gp100. Hope it's that simple for yours. Good luck.

[44man]

It could be the wrong boolit, wrong fit or wrong load for the gun.
Most Ruger's will shoot cast right from the first shot. My friends bring their guns here and except for the factory proof, none has ever seen a jacketed bullet. Just have to remove the copper from those proof shots.
Ruger barrel steel is very tough and it takes thousands of shots to even start to smooth them but they are smooth to start with. My SBH has surpassed 58,000 heavy loads and I can not detect any reduction in bore size. It still shoots like day one.

[44man]

Catboat responded as I was printing. He is correct, check the throats. That is usually the problem.

[MtGun44]

You can learn a lot from reading the sticky "basic revolver accuracy" at
the top of the handgun page.

Bill

[NHlever]

Ruger round handgun barrels (single action, and Super Redhawk) I believe are hammer forged. The other double action barrels are drilled, reamed, bore broached to put all tool marks in the direction of bullet travel, and then cut rifled. The barrel steel is very tough indeed! I was also very pleased to find that the chamber throats on my new 45 Colt Blackhawk are perfect in size for the barrel dimensions.

[MtGun44]

I wonder if that is just good luck or has Ruger figured this out and
started hitting the correct dimensions on purpose? My older, used
BH .45LC/.45ACP was very tight on both cyl throats at first, but I
reamed it up and it is better on consistency.

Bill

[crabo]

After you try the above, you can try using a Q-tip and painting LLA in the forcing cone. Also take some boolits that are sized and lubed and coat them with LLA. I used a Dixie cup, put about 10 at a time in, squirted the LLA, rolled them around and put them on wax paper. I let them dry overnight, then loaded them. No leading.

That might help you start breaking the barrel in.