@ Dellet:  Woo-hoo!  Your QL numbers are a lot different than mine.  But I'm using a 65 grain bullet seated .250 deep, and my carefully measured case capacity is only 13.0 grains water.  Maybe other factors we aren't congruent on, too.  With these tiny cases small differences have large effects.

Any event, that 3.0 of Trail Boss puts the pressure to a level that's way above what I consider kind to the old, skinny-link Favorites.  I'm trying to keep pressure to 7000 psi, which I calculate to produce about 840 lb. of bolt thrust in the .25 Stevens.  I picked that benchmark after calculating the bolt thrust of a .22 Std. Velocity.

Your load is up in the range that was, according to written sources, being bruited about for a "high-velocity" .25 Stevens before WW2.  (Barnes wrote that they were contemplating 1400 fps. from a 24" barrel.)   Now that I see the pressures, I can see why it wasn't ever done.  The weaker rifles and tip-up pistols would have been fragged before the second box was used up.

Wish I could get this Labradar to work so I could get some numbers for my factory ammo. *sigh*  Also wish it would stop raining for more than half a day.  My place is a sea of mud. 

Dellet wrote on Feb 26^th, 2018 at 12:16am:


Well, no, it was I who was doing something wrong.  Using a spreadsheet program to do the calculation, I did an entry wrong on the first line, and of course propagated it on each successive line.   

The baseline thrust, (of a .22 Std.Vel), is 400 lbs, not 800. 

Fixed that, and the rest of the argument still holds.  Assuming Std.Vel pressure to be 10,500, equal thrust calculates to 
7700 for the .25 (used case ID of .257 this time), and 
5700 for the .32 Colt.

On the corrected spreadsheet, your 17000 lbs yields 882 lbs. thrust, btw.   

Labradar would not pick up any of my .32 shots, set on pistol.  I have been wondering if the acoustic trigger needs a louder muzzle blast.  Figured to try the Doppler trigger next time.   

Jack Harrison told me that his unit performs much better with an external battery, so I now have one of those, too.  Alkaline cells don't respond to heavy current draws well, so that might be a factor.   If not using the external battery, using these new Lithium primary cells might help.  On spec they are supposed to support higher current draw.   

We shall see.

Have gotten my donkey in gear and finished up the reforming of 30 .17WSM cases - loaded five in a ladder from 1.1 to 1.7 grains Bullseye.  If my QL Model isn't flawed, 1.8 grains should net me 1000 fps at 7160 psi. 

I know there is a blackpowder section in QL, but have no more than glanced at it.  Your number looks right - Barnes says the BP load was 10-11 grains, and I've long believed that the BP MV was about 1000 fps.

uscra112 wrote on Feb 26^th, 2018 at 1:27am:


Interested to know where the 10,500 pressure number came from, I have not been able to find any actual rimfire references, only SAAMI max?

A call to CCI basically only said they load to near SAAMI pressures.

When I enter 1.8 Bullseye I get 8400 psi., 1029 fps. But that is seated at .350" which is where I need to seat the bullet I am using.

I have shot 22 lr suppressed using, Pistol & Doppler without a problem, so I think that should work fine for you.

uscra112 wrote on Feb 26^th, 2018 at 10:44am:


I wonder what pressures are estimated if you use Vihtavouri 3N37 in your model? That was actually developed for 22 rimfire.

frnkeore wrote on Feb 26^th, 2018 at 1:28pm:

From a secret squirrel source

(You need to Login or Register to view media files and links)

Quote:

uscra112 wrote on Feb 26^th, 2018 at 4:09pm:


I was wondering what the pressure would be in your 22 rf model.

uscra112 wrote on Feb 26^th, 2018 at 4:41pm:


That would tend to support your 10,500 max number.