Velocity seems too high

[Iwsbull]

I loaded some 429421 pc boolits over 8.5 grains of unique and the velocity was a good bit higher than I was expecting. 1052 with a 10 shot string mixed head stamp brass and a sd of 11. This is out of a 7 1/2” Super Redhawk. Well above what my Lyman book said. Have y’all ran into this before? I seared to the crimp ring.

[Wheelguns 1961]

First thing. What was the test firearm? There are many factors that affect velocity in a revolver, including B/C gap, barrel uniformity and smoothness, etc. I know that in my cast bullet handbook, the test firearm is a 4” universal receiver. I am not an expert, but this is not unusual.

[bmortell]

my notes: 6.5" SBH 240swc 10.5gr unique 1160fps, 11.5gr 1220fps.

lyman is a bit like that

[Larry Gibson]

Lyman uses a 4" test barrel for their 44 magnum velocities.

[Iwsbull]

It just kinda puzzled me that Lyman listed a starting load of 9.8 at 912 FPS and being close to 1 1/2 grains lower I had much better velocity. I guess as fast as unique is I was not expecting the extra barrel length to make that much difference. I will say that the 8.5 load was mighty accurate and it may become my all around load from plinking to deer and hogs.

[Groo]

Groo here
Also remrember lead boolets are faster than jacket [often 100 fps in heaver loads] due to the
hardness of the jacket...

[kingrj]

This seems perfectly normal data to me....

[Larry Gibson]

255 gr RCBS 44-250-K over 8.5 gr Unique in W-W cases with WLP primer; 4" Colt Anaconda ran 930 fps, 6 1/2" Ruger FTBH ran 1010 fps.

My standard 44 Magnum load for general use these days is this 8.5 gr load with a 240 - 260 gr bullet (my own cast or commercial). Recently acquired a 4 cavity Lyman 429421 mould (from Lloyd....thanks again) and will be casting some bullets with it shortly. They will be loaded over 8.5 gr Unique.......

[RED BEAR]

Lyman uses a 4" test barrel for their 44 magnum velocities.

Well this solves it .

[onelight]

There is a good article in the Speer #9 manual on page 348 “Why ballisticians get gray” they checked the same loads through a lot of different guns with different results.
Good article if you have that manual .

[georgerkahn]

I shot same bullet over 8.0 gns Unique, CCI regular primer, mixed brass in a "Dirty Harry" 6.5" Smith, and fellow at range chronied them at an average (six shots, ea) of 912fps, and 940fps, respectively. If I had similar results as yours, out of a 7 1/2" bbl Redhawk, I'd not at all be too concerned. Bion, I have noted chrony set-up and brand do make a difference, too. Mine is an Oehler 35p; fellow at range had a PACT. Regardless, you use a one-half grain more of same powder, and gain a tad more velocity -- apparently velocity and powder charge is not a linear function -- so again, I'd not be too alarmed.
geo

[Don Purcell]

Out of a 7 1/2 inch barrel your load is spot on. Run with it and have some easy efficient fun.

[Outpost75]

Also consider that differences in barrel-cylinder gap affect velocity.

A short-barrrel revolver set up to minimum factory tolerance (pass 0.002/hold 0.003") may produce higher velocity than a longer-barrel revolver having a wider gap greater than Mean Assembly tolerance (pass 0.005/hold 0.06) and will certainly be faster than a loose gun at Customer Service Maximum (pass 0.008/hold 0.009).

Those were Ruger specs the factory built to in the 1980s. I have recently observed new guns of both S&W and Ruger manufacture with huge B/C gaps which wouldn't have been allowed to ship in my time...

[onelight]

Also consider that differences in barrel-cylinder gap affect velocity.

A short-barrrel revolver set up to minimum factory tolerance (pass 0.002/hold 0.003") may produce higher velocity than a longer-barrel revolver having a wider gap greater than Mean Assembly tolerance (pass 0.005/hold 0.06) and will certainly be faster than a loose gun at Customer Service Maximum (pass 0.008/hold 0.009).

Those were Ruger specs the factory built to in the 1980s. I have recently observed new guns of both S&W and Ruger manufacture with huge B/C gaps which wouldn't have been allowed to ship in my time...
A shooting buddy just got a new gp100 it was .0015 to tight .

[Outpost75]

A shooting buddy just got a new gp100 it was .0015 to tight .

MUCH easier to deal with than loosey-goosey, when you must either set the barrel back or refit a different cylinder! But at 0.0015 a gun my bind when it gets hot, or with just a bit of lead fouling.
If you have the Brownell's facing cutter, bushings and T-handle, a simple fix.

[onelight]

I found part of the article from the. Speer manual
http://www.leverguns.com/articles/ballisticians.htm

[rintinglen]

A "snug" barrel with a tight barrel cylinder gap can markedly elevate pressures and consequently velocities. My old buddy Rick had a 5 1/2 inch Redhawk that had a narrow BC gap ~.003 and a .4285 groove diameter barrel. It ran 75 fps faster than my 7 1/2 incher with identical loads.

[onelight]

MUCH easier to deal with than loosey-goosey, when you must either set the barrel back or refit a different cylinder! But at 0.0015 a gun my bind when it gets hot, or with just a bit of lead fouling.
If you have the Brownell's facing cutter, bushings and T-handle, a simple fix.
It’s new so Ruger would fix it I’m sure , it will only be a range gun and he wants to shoot as is but it does not take much to bind it up. He is also learning a Dillon 550 he just got and had few high primers just barely high and they put it in a bind. He is a retired detective and has loaded and shot for many years so he knows the situation and gonna see if it will loosen up with some range time.