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Dillon Blue

2 new vaqueros with 50fps difference in velocity

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Just picked up my son who shoots SASS,  2 new Vaqueros last week.   Ran about 50 rounds through each then went to chrono my ammo for these guns.  One gun is running 695 fps average and the second was running at 645fps average.   SD was 9 and 10  between the pistols.  The guns are sequential serial numbers.  Ammo was made on a Dillon of course at the same time.

 

Any ideas on this?   Is it anything to be concerned with?  Both are accurate with load.  Just thought it was odd to see such a variation in speeds.

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Have  you slugged the barrels and checked the throat diameters of the two guns? If the throat diameters on all six chambers of each cylinder are off by several thousandths of an inch, that could account for it.  So could differences in barrel dimensions.  If both guns shoot where you point 'em then don't worry about it.

Stay well, Pard!

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50 minutes ago, Trailrider #896 said:

Have  you slugged the barrels and checked the throat diameters of the two guns? If the throat diameters on all six chambers of each cylinder are off by several thousandths of an inch, that could account for it.  So could differences in barrel dimensions.  If both guns shoot where you point 'em then don't worry about it.

Stay well, Pard!

 

I have 2 Vaq in .32 H&R that USED to have the same problem.

 

My problem was exactly as Trailrider stated.   Get a competent smith to uniform those chamber throats and that should help.

While your at it, have them check out your forcing cone for each pistol and slug your barrels.

 

..........Widder

 

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Or just don’t worry about it. We’re not shooting bullseye and minimum power factor is of no consequence!

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And check the cylinder/barrel gap.

 

Be careful about slugging your barrels.  I did that one and my knuckles still hurt!  :D:D

We're here all week.

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I'm sure it can be fixed as suggested, but I wouldn't worry about it.

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PLUS ONE too EVERYBODY above.  

 

You should probably have the cylinder throats looked at.  Ruger is famous for too small throats.  But, if the guns are both accurate with the load, I'd leave them alone.

 

PS:  Tight throats will give you increased felt recoil.

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50 fps difference between 2 production handguns is nothing.

OLG 

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8 minutes ago, The Original Lumpy Gritz said:

50 fps difference between 2 production handguns is nothing.

OLG 

Normal variation.  I bet half the CAS pistols in use today have at least that much variation.  Nothing to lose sleep or spend money over.  IMHO. 

 

Did you look at velocity variation within each pistol?  Just curious what it was.  My loads in the same pistol usually vary by 30-40 fps.   Barrel heating alone can change velocity by that much. 

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3 hours ago, Marauder SASS #13056 said:

And check the cylinder/barrel gap.

 

Be careful about slugging your barrels.  I did that one and my knuckles still hurt!  :D:D

We're here all week. left hand or right?

 

3 hours ago, Marauder SASS #13056 said:

And check the cylinder/barrel gap.

 

Be careful about slugging your barrels.  I did that one and my knuckles still hurt!  :D:D

We're here all week.

 

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There Are Slow Barrels And Fast Barrels ,,,, Just a fact of life ...

Two Rifles In .270 Winchester Both with SAMMI minimum spec Chambers with No measurable differences on fired brass ...

One with a 24 inch barrel and the other with a 26 inch barrel ,,, While working up loads the same loads were fired in each gun, the 24 inch gun produced lower pressures and an average of 80 FPS. more velocity all the way up until  Max. Pressures where reached in the 26 inch gun ...

At this point the shorter barreled gun was producing 112 fps. more velocity at 9,000 PSI. less pressure ...

When the 24 inch gun was loaded to the same PSI. level it produced 180 PFS. more Velocity than the 26 inch barreled Gun ...

And produced three, three shot Groups at 300 yards that were all under 1.5 inches ...

The Best the Heavy barreled 26 inch gun could do was groups averaging 2.1 inches ...

 

Jabez Cowboy 

 

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No concern.  My are worse.  The bullet only has to go ding.

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I prefer my bullets (cartridges)  to go bang

 

And the targets to ding :D:D:D

 

 

 

Velocity consistency and accuracy are more important that the variance between guns.

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I would shoot and clean them a few times before I did anything.  Then if the issue remains and bothers you look to the throats

 

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Would be curious what the barrel/cylinder gap is on both revolvers.

OLG 

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21 hours ago, Boggus Deal #64218 said:

Or just don’t worry about it. We’re not shooting bullseye and minimum power factor is of no consequence!

And with a single digit SD and pleasing accuracy, I'd say both are real keepers.

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Ding, Bang, Dead, Edger all good:rolleyes:.

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I'd be willing to bet most of us have never checked our pistols for velocity inequality. Normally, I just grab the pair I want to shoot and go shoot. 

Don't overthink all this, it's not worth the effort unless you're shooting bench rest or maybe silhouettes. 

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One of the older Speer manuals (i think it was number 9) had a section about why ballisticians have gray hair that addressed this subject.

 

Duffield

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1 hour ago, Duffield, SASS #23454 said:

One of the older Speer manuals (i think it was number 9) had a section about why ballisticians have gray hair that addressed this subject.

 

Duffield

One reference in that article was 2 S&W revolvers chronoing 125 fps apart.   Interesting read       GW

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Thanks for all the responses.    So far the guns have shot great at paper and he ran a match with them last weekend with no issues.  No reason to fix what aint broke I guess.

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Howdy

 

Just so you know, sequential serial numbers with Ruger revolvers really doesn't mean anything.

 

The frames were stamped sequentially, and it ends there. Nothing was done to tweak the revolvers to make them perform similarly.

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