New gun let me down

[feets]

Or did I let myself down?

I picked up my purty new-to-me 7-1/2" Redhawk in 45 Colt and took it to the range this morning. It was a little face-off between my Super Redhawk and the newcomer Redhawk, both using 45 Colt.
The Redhawk was very clean seemed to be in great mechanical and cosmetic condition.

First up was a batch of lightweight Cowboy loads. 265 grain lead over 5.5 grains of Trail Boss. The SRH chuffed and put together a fair group of holes in the paper, all within 2" of one another. The Redhawk puffed a few rounds here and a few rounds there. It was kind of hard to see the grouping since they scattered badly and I had sighted in the scope on my 45 Colt Contender using the same target.

Fresh targets went up and I stepped up to real ammo.

This round of shooting was done using 270 grain Thunderheads over 18 grains of 2400. Here's what the SRH had to say:

The Redhawk answered with this:

That was a little annoying so I changed to 255 grain round nose lead over the same 18 grains of 2400.

The SRH did this:

The Redhawk followed with:

I had a couple more loads to run as well. All loads had about the same results. The SRH worked well for me and the RH ended up in it's Wonderland, as in I wonder where it will land.

The gun is tight. I broke out the machinist tools and took some measurements.
The cylinder bores on the RH are consistent at 0.4509 and the SRH is 0.4516.

The lead I was shooting today all came in around .452 so that shouldn't be too much of a problem.

The cylinder gap on the RH is .0045" minimum and .0085" at maximum. That gives me .004" in thrust.
Cylinder shake seems to be the same between both guns but I didn't set up a fixture to measure it.
Both barrels have similar crowns.

If there' s a mechanical issues I'm not sure what it is.


I dug up a little info on my gun. I looked at Ruger's site. They list the start dates for the serial numbers online. The first Redhawk produced in 2013 wore 503-65138. My gun is less than 100 numbers off the 2013 starting number.
Ruger has not made 7-1/2" guns in 45 Colt since 2007 by what I can tell. Here are the current offerings in the Redhawk line.
Catalog number, model number, caliber, and barrel length
KRH-44 5001 44 Rem Mag 7.50"
KRH-44R 5003 44 Rem Mag 7.50"
KRH-445 5004 44 Rem Mag 5.50"
KRH-444 5026 44 Rem Mag 4.20"
KRH-45-4 5027 45 Colt 4.20"

The box for mine says KRH-45 5023 45 Colt. I'm thinking it must be some sort of distributor exclusive. I was afraid it might be a parts gun or something like that.

I guess I'll load up more test rounds and let a friend fiddle with it.
I've got some .451 and .452 jacketed stuff from 185 through 300 to run next time around to see if it likes that better than my lead.

Perhaps I'll take the pistol rest with me next time to see if it was me or the gun.

Any other suggestions?

 

[Hondo 60]

You say the chambers are 0.4509 on the RH

Is it possible that your chambers are tighter than the barrel?
That would allow the bullet to bounce down the barrel.

That's where I'd start.

 

[feets]

The chambers are about the same as my Vaquero and it doesn't have this problem.

 

[Old Fuff]

Shoot 3 to 5 rounds in a single chamber, using seperate targets for each of the six chambers and see if you have one or more that are throwing wild shots. If some of them aren't concentric with the bore they could be the source of you're problem.

 

[il.bill]

Shoot 3 to 5 rounds in a single chamber, using seperate targets for each of the six chambers and see if you have one or more that are throwing wild shots. If some of them aren't concentric with the bore they could be the source of you're problem.

Thanks for a great tip. I have a couple of revolvers I bought used and will be trying that out the next time I go shooting. They consistently seem to have a shot or two well off the grouping.

Three to five shots from each chamber using six different targets - a very simple and elegantly effective diagnostic approach.

 

[huntershooter]

I think you've answered your question.
.4509 throats are too tight for .452" bullets. They are swaged to throat diameter and won't obturate/"slug up" to bore diameter.
My experience with Rugers in .45 Colt (and S&W's in .44 AND .45 Colt) of recent manufacture has been the throats are frequently too tight.
Get a Manson throat reamer and finish ream the cylinder throats. Accuracy will be substantially better with cast bullets.
I'm willing to bet a .451" jacketed bullet will shoot much better than the lead; which is frequently the case with too tight throats-the copper jacket is "springier" than lead and has a chance of obturating.

 

[Walkalong]

That would be my bet as well. Better than way over sized throats. You can ream these to the perfect size, or have someone do it for you.

 

[osteodoc08]

Ream the throats. My dad has had to do that on all his 45LC regardless of brand.

 

[murf]

slug the barrel. throat diameter should be at least .001" larger than groove diameter. your redhawk barrel grooves may be .451".

are you having a throat/barrel leading problem with that gun?

how are you measuring those throats? the ten thousandths accuracy of your numbers is why i'm asking. also, measure all six throats and give us a variance.

murf

 

[Old Fuff]

Thanks for a great tip.

You're welcome. During the dim past of the last century serious bullseye target shooters often did this. It may also give you a clue concerning too-tight chamber throats if the larger ones do better.

 

[feets]

slug the barrel. throat diameter should be at least .001" larger than groove diameter. your redhawk barrel grooves may be .451".

are you having a throat/barrel leading problem with that gun?

how are you measuring those throats? the ten thousanths accuracy of your numbers is why i'm asking. also, measure all six throats and give us a variance.

murf

I used a telescoping gauge and a micrometer to measure the bores. I just took multiple measurements of each bore again. Gotta be careful rocking a telescoping gauge in a bore this small. It's on the bottom end of my gauge's ability. The edges of the pins will hit if you rock it a wee tiny bit too much.

.4513
.4513
.4509
.4508
.4513
.4515

These things are tight. I can't drop a bullet measuring .4512 through any of the bores. It can be tapped through without much effort.

I measured the SRH again. I blew that one the first time. It averages .4554. It's the Vaquero that averages the .4516 I listed previously.

 

[murf]

ok. now, can you measure the bore diameter of the barrel with that setup? if you can fit the gauge between the lands, measure that diameter, too.

have a feeling the barrel groove diameter is more than those throats. if so, the suggestion to ream out the throats will be a good one.

how does the vaquero shoot that load? any leading problems with it?

ruger had a problem with .450" throats and .451" barrels a while back. accuracy, from what i read, sucked.

murf

 

[feets]

I get .4515 on the lands and .4525 in the grooves. Kinda hard to get it exact but I'm comfortable with those numbers.
I might try to slug the barrel to see what that gives me.

 

[feets]

Slug came through at .4517 with lands down to .4437 to .4443.

The slug was much harder to push through the bore when it got to the frame. I can't get a reliable measurement at that part of the barrel but I've found .4447" twice.

I wonder if the barrel is screwed into the frame so tightly that it's being squished down a wee bit. If so, that would explain a bullet rattling down the bore afterwards.

 

[huntershooter]

You are correct.
Slug the bore (oversize fishing sinker) and see what you get.

 

[feets]

I ran an oversize soft lead bullet through the bore and got the numbers I posted above.

 

[moxie]

On the other hand, maybe you just don't shoot that gun very well.

I once had a RH 7 1/2 bbl. in .44 mag. Shot groups like yours no matter what rounds, factory or reloads, I put through it, even with a Nikon 2X on it. The RH has a very long trigger reach that could be causing problems for you.

Finally traded it away.

 

[Vern Humphrey]

The slug was much harder to push through the bore when it got to the frame. I can't get a reliable measurement at that part of the barrel but I've found .4447" twice.

I wonder if the barrel is screwed into the frame so tightly that it's being squished down a wee bit. If so, that would explain a bullet rattling down the bore afterwards.

That's almost certainly at least part of the problem. Try slugging the bore until it hits the "wall" at the frame, then tapping it back out the muzzle, and comparing that slug with the one you drove all the way through the bore. I'm willing to bet there will be a significant difference.

If there is, I'd contact Ruger and see what they'll do to fix the problem.

 

[huntershooter]

If the barrel is "crushed"/bore constricted- where it fits into the frame there's not a lot you can do to resolve it.
As said, contact Ruger and see what happens.
The only other option I'm aware of is "Taylor Throating" (Google it for a consise description).
Simply put; a reamer removes the rifling from around a half inch +- from the forcing cone forward. This would remove the constriction created at the barrel/frame.
I have no personal experience with Taylor throating, I have read both pro and con opinions of the procedure.

 

[feets]

Ruger is closed this week.

 

[moxie]

In the meantime, have someone else try it. See if they have a problem too.

 

[jim8115]

I had a 454 SRH 71/2 " that shot great, i traded it for the same gun in 9 1/2" and nevr could get it to shoot right. I traded it off

JIM

 

[rswartsell]

Minor point,

There is no purty Redhawk. Damn fine revolvers, damn useful too. Maybe the best of the breed? Could be. Purty?

 

[feets]

Beauty is in the eye of the beerholder, er, beholder.

I'm a mechanical fiddly bit kind of guy. That gives me a great appreciation of machines, both small and large. Big solid revolvers hold a special place in my heart.

Yes, I REALLY enjoy my N-frame but it's far more delicate than this Redhawk.

 

[murf]

feets, did you clean all the lead out of the barrel before you ran the slug through?

if not, you will need to do it again. that may be the restriction you felt at the forcing cone end of the barrel. check the forcing cone for lead while you're at it.

if you want to fix this accuracy problem you will have to ream out those throats to .4525" or more. you can do it yourself with a manson reamer from brownells, or you can send the gun to a smith. regardless, this is the first step in fixing the problem.

let me know on the cleaning issue.

murf