Problems with new RH spraying patterns not groups

[feets]

I just picked up a RH in 45 Colt. It's a 7-1/2" barrel with a serial number less than 100 units before the 2013 production run. The box states it's catalog number KRH-45 (not KRH-45-4) and model number 5023. That makes me believe it's some sort of distributor special or similar odd ball gun.

I ran it alongside my SRH in 454. The loads that grouped under 1-1/2" in my SRH ran over 8" in the RH at a distance of TEN YARDS.

I tore the RH down for detailed inspection. The cylinders run .4508 to .4515 in diameter. I can't drop a .4512" bullet through any of the chambers but it will pass with light tapping (no hammer required).

When I slugged the bore I found that the slug got VERY tight where the barrel screws into the frame. It came out with lands measuring .4437 to .4443. Just for giggles, I realigned the slug and pushed it through again. I could press it into the bore with my fingers and it tapped easily until I got to the frame again. That's when I had to put down the rubber mallet and get a metal hammer to tap on the rod.

Is it common for Redhawks to have barrels screwed on so tight they squeeze down that far? Could that be the cause of my accuracy issues?

 

[Chuck 100 yd]

I sent the cylinder from my 7 1/2" RH .45 Colt to cylindersmith.com to have them reamed to .4525 and that cut my groups in half. So far I haven`t slugged the bore but it shoots quite well,at least as good as I can. The choke at the thread area is another thing. I would be calling Ruger on that one. Good luck!

 

[s4s4u]

measuring .4437 to .4443

That is a significant constriction.

 

[mohavesam]

Give Ruger a call. Be detailed in description.

 

[feets]

Ruger is closed this week. I'll have to call them next week.

 

[Silent Sam]

That bullet is a hotdog in a hallway past the frame.

 

[5of7]

I have noticed a tight spot where the barrel screws into the frame and Ruger guns and also on the later S&W guns that do not have pinned barrels.

For the bore to be constricted that much is a little hard to imagine. Usually it is a matter of from .0002" to .0005" which can be lapped out if desired.

If you are sure of your measurements, I would send it back to Ruger for a new barrel. 8)