'51 R-M and '72 Open Top shooting results

[PJ Hardtack]

My long awaited Uberti '71 Open Top in .38 Spl. arrived yesterday, along with an 'as new' Uberti/Cimarron '51 Navy conversion, also in .38 Spl.; both with 7-1/2" barrels.
It was 18*F/-6*C and the roads were icey, but I had to go shooting .....

First up was the '71 and it put 10 rds into 3" at 12 yds, Duellist-style, 3" high of the POA. Perfect! Then I fired 15 rds at the 50 yd 10"x12" gong with both hands, using a centre hold and hitting every time! Load was 3.5 Red Dot/158 SWC. That's minute-of-steel Cowboy and more I couldn't reasonably expect.

The Uberti/Cimmaron '51 was a disappointment. A previous owner had lightened the hammer spring to the point where 3 out of 5 rds failed to fire. Hits were dead centre on the primer, but too light to ignite. Primers were Winchester small pistol, not Federal.
I'm going to order a new hammer spring, but in the meantime, is there something I can do to re-tension the old spring?

The two rds that did fire did not print anywhere near POA and I suspect that had something to do with less than ideal ignition due to the light hammer fall. Am I right?

[Abilene]

Nice accuracy with the Opentop.  As for the Navy conversion - see if someone put a washer under the mainspring.  If so, remove it and you will get a little more hammer tension.  If not, could be that the previous owner just used Federal primers.  You might be able to bend the mainspring but you do chance breaking it.  The mainspring on the OT and conversions is the same as any Uberti or Colt SAA or '51/'60 percussion, so you might have one of them lying around or be able to find one without having to order one.  Also, look at the firing pin.  Conversion firing pins are different from OT FP's, but can be sharp and pierce primers.  Look to see if it appears to have been filed down to dull the point somewhat, as it is possible it was filed down too far which could contribute to the problem along with the light mainspring.  Of course any rubbing of the sides of the hammer sides against the frame could also be a factor.

Regarding accuracy, I think that a primer either goes off or it doesn't, so I wouldn't necessarily blame accuracy on a primer igniting a cartridge more slowly.  However, a lighter mainspring does affect locktime, and the slower-falling hammer can have an effect on accuracy if the gun is not shot from a rest.  Is it shooting high?  How high is the front brass post sight?  Older '51 R-M's (all four of mine) have a front sight that is approximately .125" tall and they had a tendency to shoot high.  A few years back Uberti changed the front sight to a much taller one (maybe .25" tall?  I'm not sure) to help with elevation.  I'm really not sure how accurate my '51 R-M's are, as I haven't shot paper for years    I have shot a number of clean matches with both the 5 1/2" and 7 1/2" guns so I guess they are "minute-of-steel cowboy" as you put it and good enough for me 

Good luck.

[PJ Hardtack]

Abilene - thanks for the response!

No washer under the mainspring. First thing I checked. I'll be ordering a couple of springs and other spares today from VTI. In the meantime, I have several other guns I could scavenge from just to shoot the gun.

I have long detested the 'dead' feel of 'tuned' guns with soft hammer falls - rifle or pistol. I prefer a nice' definite 'snap' in a hammer fall. A well meaning friend installed a new mainspring in my 44-40 Henry after the original spring broke. I thanked him and promptly replaced it with a new spring.

In my IPSC days, I shot my S&W 66s with full weight factory springs. It never failed to go 'Bang!' unlike a lot of 'tuned' guns that would misfire even with Federal primers. Adrenalin is a powerful thing, in competition or on the street.

As for the '51 conversion shooting high, I don't know why it didn't occur to me that like a '51 cap & ball gun, the conversion would be similar. Solution - have a dovetail milled for a higher front sight.

[Hoof Hearted]

PJ

Abilene hit it all "right on the nose" with his well thought out and perfectly explained answer here!

Regards
HH

Nice accuracy with the Opentop.  As for the Navy conversion - see if someone put a washer under the mainspring.  If so, remove it and you will get a little more hammer tension.  If not, could be that the previous owner just used Federal primers.  You might be able to bend the mainspring but you do chance breaking it.  The mainspring on the OT and conversions is the same as any Uberti or Colt SAA or '51/'60 percussion, so you might have one of them lying around or be able to find one without having to order one.  Also, look at the firing pin.  Conversion firing pins are different from OT FP's, but can be sharp and pierce primers.  Look to see if it appears to have been filed down to dull the point somewhat, as it is possible it was filed down too far which could contribute to the problem along with the light mainspring.  Of course any rubbing of the sides of the hammer sides against the frame could also be a factor.

Regarding accuracy, I think that a primer either goes off or it doesn't, so I wouldn't necessarily blame accuracy on a primer igniting a cartridge more slowly.  However, a lighter mainspring does affect locktime, and the slower-falling hammer can have an effect on accuracy if the gun is not shot from a rest.  Is it shooting high?  How high is the front brass post sight?  Older '51 R-M's (all four of mine) have a front sight that is approximately .125" tall and they had a tendency to shoot high.  A few years back Uberti changed the front sight to a much taller one (maybe .25" tall?  I'm not sure) to help with elevation.  I'm really not sure how accurate my '51 R-M's are, as I haven't shot paper for years    I have shot a number of clean matches with both the 5 1/2" and 7 1/2" guns so I guess they are "minute-of-steel cowboy" as you put it and good enough for me 

Good luck.