Big Bore Magnum Snub Nose Velocities

[AxeHandle]

Spinning through Ruger web pages. Stumbled upon a statement that said to expect a 300FPS loss from the 7.5 inch SRH to the 2.5 inch SRH. Works out to 60 FPS per inch. Easily saw that kind of loss with the 454 Alaskan. Plan in place to chronograph the 44 and 480 soon.

[bula]

The 480 may surprise you. 

[AxeHandle]

If nothing else the process will provide simple justification to pick up a 7.5 inch barrel 44/454/480 SRH

[dave19113]

Here is a webpage a guy supposedly did testing of various calibers by the inch to show velocity loss or gain.

It does not have 480 specifically but it does show some interesting findings on barrel sizes



www.ballisticsbytheinch.com/calibers.html

[lockhart]

Most of the big caliber revolvers ( 454, 500 what-ever,etc) their top velocities
are obtained in the LONGER barrels! But, some will buy the little snub-nose varieties
and expect the same velocities! It aint happening, folks!

[bula]

It's my thought that the cartridges that make their reputation by using lots of slow burning powder and needing high pressures to meet their hype, are penalized more as tubes get shorter. IMHO.. I get it that you may want the snubby to be a companion piece to a longer barreled version and so take what you get, in the way of performance, blast. 

[potatojudge]

There's enough variables you won't really know until you chrono your loads in your guns. The fps/inch holds true for an average of many samples, but doesn't tell you much about your individual gun.

You don't really need more than 1000 fps in these rounds for any real-world purpose, and they can hit that easy in a short barrel. It just comes at the expense of pressure and blast vs achieving the same velocity in a longer barrel. Not a big deal really. Not judging if anyone wants to push max velocity in these guns either, that's all in good fun too.

I think that 480 is the best (really) big-bore factory option on the market, and would happily own one.

[bradshaw]

When other dimensions are equal, longer barrel equals free velocity. While a light bullet accelerates faster, its lower inertia decreases burn efficiency. A low velocity bullet uses less energy to push the air in front of it, thus holding velocity for a given distance. The faster a bullet, the faster it slows. However, velocity still means energy: a 100 fps difference at 900 fps affects performance more than a 200 fps difference at 2,000 fps. Having a means to test behavior, such as water jugs, yields good information.

Deep seating of a heavy bullet contributes efficiency from a short barrel. Weight tends to be more predictable than the absence of weight.
David Bradshaw

[bigbore5]

I don't own a 480 yet, but often shoot a 435gr swc from an Arsenal mold at 825fps from the 475 Linebaugh. Very tolerable recoil and extremely accurate. Never recovered a bullet from any of the 14 pigs, 4 whitetails, or the 390 pound black bear I have shot with it. Big heavy bullets don't need max velocity to do the job.

[edk]

It is certainly understood that the 480 is favored around these parts for shooting the MP mold bullet at subsonic velocity. That having been said, load the 480 to full 48 KPSI spec and I would wager the loss of velocity is going to be in the same ballpark as the 454.

[gnappi]

You're fortunate to have those on hand to test, that .480 may be a hoot to shoot.

[paul105]

Here are a couple of data points:

480 Ruger
385gr Miha FNHPPB Coated by Sixshot
Seated to and crimped in bottom grove
22.4gr H110, WLP, New Starline 480
Chrono 5 long steps from muzzle
5 shot average

RSRH Alaskan 2.5" ..... 75 deg F ... 1,021 fps
Freedom Arms M83 6" ... 50 deg F ... 1,246 fps

Paul

[gnappi]

Apr 8, 2023 10:31:27 GMT -5 paul105 said:

Here are a couple of data points:

480 Ruger
385gr Miha FNHPPB Coated by Sixshot
Seated to and crimped in bottom grove
22.4gr H110, WLP, New Starline 480
Chrono 5 long steps from muzzle
5 shot average

RSRH Alaskan 2.5" ..... 75 deg F ... 1,021 fps
Freedom Arms M83 6" ... 50 deg F ... 1,246 fps

Paul

Very cool! I doubt the 25 degree temperature delta had much effect. 

I once went to an IPSC match in Rhode Island (not USPSA) in January with snow on the ground. I kept my .45 ammo in mags in my hand inside my pant pockets and when it came time for them to chrono everyone's loads my S&W 745 with 210 grain LSWC ammo was the only gun (most with .45's the rest with supers) to make major of maybe 30+ shooters. :-)