Python Velocity

[Texasred]

I was looking at the Ballistics by the inch website and I noticed the 6" python has unusually low velocities. Even compared to the snubbies!
I own a 6" and while appreciate all the other merits of this gun. Accuracy, aesthitics, and appreciation of value of course. It makes me wonder why the low velocity. Is it the tapered bbl that may actually slow down the bullet in order to maintain ultimate accuracy?

http://www.ballisticsbytheinch.com/realgap.html

 

[rcmodel]

One gun, one set of tests.

The next Python to come along might be the fastest one in the test.

The reasons are many and varied, but could include a worn out gun with excess end-shake & barrel/cylinder gap.

rc

 

[jmr40]

True, but some manufacturers have a tendency to shoot faster or slower than other brands. I've shot enough rifles to notice some trends. Less chronograpy work with handguns, and none with a Python, so I can't comment much on Pythons specifically.

Things such as the type of rifling, the tolerances of the barrels, and cylinder gaps all come into play.

 

[Waywatcher]

Every time I've seen gun vs gun chronograph tests, the Python always loses. Not sure what it is...

 

[dfariswheel]

In addition to the tapered bore, the Colt's including the Python used a faster rifling then most other pistols.

Possibly the combination of bore taper and fast rifling slows the bullet down slightly.

 

[pendennis]

Here's a link to an article by Dave Andrews. It was done back in the 1970's. It details the tests that Speer did in comparing a number of .357 magnum revolvers with identical (as can be done) loads. Note that the three Pythons and three S&W Model 19's, have variances of over 200fps between the three samples.

http://www.leverguns.com/articles/ballisticians.htm

 

[saltydog452]

No chronograph results, but 3 Pythons and one SAA New Frontier had tight bores of .354/.355. That was with a .36 lead ball driven through the barrels and measaured electronically by a QC Inspector.

I sent three of those balls to Colt asking for their comments. The reply from Colt said stuff that starting in the mid 30s or so, the top end revolvers got the tighter tubes.

If you look closely, you might find that the .357 Python has the same cylinder length as their .38 Colt Officers Match.

Products from Hartford are certainly different now. My experience was from mid 70s.

Using a smaller diameter expander plug, you can successfully reload 9mm (.354) jacketed bullets in .357 cases for the early Pythons.

Betcha that'd jack up the speed some.

salty

 

[mmitch]

Was it possibly the .38 special-only iteration of the 6" target Python?

Mike

 

[dfariswheel]

Colt didn't make a 6" .38 Special Python, only an 8" version.

 

[Old Fuff]

No chronograph results, but 3 Pythons and one SAA New Frontier had tight bores of .354/.355. That was with a .36 lead ball driven through the barrels and measured electronically by a QC Inspector.

I sent three of those balls to Colt asking for their comments. The reply from Colt said stuff that starting in the mid 30s or so, the top end revolvers got the tighter tubes.

According to my pre-war Colt blueprint the standard grove diameter for .38 S&W (aka Colt New Police) and .38 Special was .353" - .354" with a .3585" chamber throat. These dimensions presumed the ammunition was loaded with soft lead bullets.

Note: Colt Police Positive .38 revolvers using .38 S&W ammunition will probably do better with .356" to .358" bullets rather then the standard .361" size. Be sure if you reload to match the inside neck sizing plug for whatever diameter bullet you are using.

I presume that the above dimensions were also used in Colt .357 Magnum barrels after 1935.

 

[1911Tuner]

There are several factors that affect revolver velocity. One is usually overlooked. The forcing cone.

Ruger revolvers have always had a reputation for "shooting fast" with a given ammunition lot...even with identical barrel/cylinder gaps and nearly identical chamber throats.

The clue is that Ruger forcing cones are set at 5 degrees. Bill Ruger optimized his revolvers for jacketed bullets. Even the early .357 Blackhawks had gently tapered forcing cones, and that was back in the day when the only jacketed bullets available for the caliber had to be hand loaded. The practice consistently produced higher velocities than those seen in Smith and Colt revolvers. Additionally, his chamber throats tended to be a little tighter.

A few years back, a friend of mine sent a 6.5-inch .41 Blackhawk to a revolversmith for accuracy work. He told the wrench that he planned to use cast bullets almost exclusively. The smith cut his forcing cone at the accepted 11 degrees...optimum for cast bullets...and opened up the throats to 4105 inch. When he got the gun back, it was scary accurate with his cast 210-grain SWCs and 18 grains of 2400. It was equally accurate with his general purpose load with the same bullet and 9 grains of Unique...both known to be superb loads for the .41 magnum.

Curious to see if the velocity had changed...hoping for an increase...he was surprised to find that he'd lost nearly a hundred fps with the 2400 load, and about 60 fps with Unique.