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Marshall and all others with useful input, I have some questions about developing a maximum hunting load for my Ruger Bisley six shot 45 Colt. I have read your excellent article in the tech notes section and have a few points I would like clarification on. First question has to do with the use of H110 and the comment you made about how it performs best in the top 5% of the pressure envelope. This is somewhat confusing to me because that top 5% is different for a 6 gun versus a 5 gun. Does H110 perform best at 30,000 CUP or 40,000 CUP? The powder does not know if it is being used in a 5 shot or a 6 shot. Also I have heard it said that H110 does best with some compression from the seated bullet. The Cast Performance 335 has 0.45” of its bullet extending into the case. What powder charge would be required to get some compression? Next question has to do with the aspect of extreme spread. You said that as the max load is approached the ES should drop, very possibly into the single digits. I have yet to see this happen. I generally am getting ES figures in the 50 fps range. Is this a sure sign that I have not reached a safe max load yet? Finally I have a question regarding velocity. As previously posted I was getting some insanely high velocities from my load using H110 and the Cast Performance 335 grain bullet. 22.2 grains of H110 gave me 1500 fps. More likely the true velocity was about 1300 fps. 21.7 grains gave a velocity of 1470 fps and 22.7 grains gave 1540 fps. Extreme spread was from 30 to 60 fps. So since the velocity had not flatlined is it safe to assume that I could keep going up and up and up in powder charge until the velocity did flatline or does that only apply to 5 shot loads? I do not feel a need to change this load as it is plenty fast even if the actual velocity is only 1250 fps (in particular the 22.2 grain load as it gave a 2.0” group at 55 yards with open sights- my best ever even when I had a 2x scope attached) but am still curious about these things. Thanks, Brian Carlson.
 

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Brian,

A few notes in answer to the above post.  First, althought the principles outilined in the tech note you mention to all handgun load development, the article was centered around the .454 Casull.

Link to article "Max Loads" & Handguns:

<a href="http://beartoothbullets.com/tech_notes/archived_tech_notes.php/15" target='_blank'>http://beartoothbullets.com/tech_notes/archived_tech_notes.php/15</a>

When dealing with the .45LC as you are, I think that it would be safe to conclude, from the information you posted on this thread, as well as your previous one, that you have found an outstandinly accurate load using the CP 335 grain bullet.  I think you stated on the previous thread something around 2" or less groups at 50 yards.   That's meat in the freezer every time type of accuracy.   Do you need more?

Next, you mention that that particular load is somewhere between 1300 and 1400 fps in velocity.   What needs more killing in North America?  With that bullet anything approaching 1200 fps. is more than plenty!

Finally you are concerned about the ES in your gun hovering around 50.  That is not an entirely bad range to be in, when you have a load that shoots as well as you have reported, at the velocities attained with a 335 grain bullet!  In that article you'll notice that I said that the ES often times approaches single digits with a well tuned load.  That doesn't mean you'll ALWAYS get that kind of consistency.  Individuality of revolver can play a big role in that part.  Cylinder to barrel clearance perhaps being the biggest culprit here.  Don't sweat the 50 ES figure with the performance you are already acheiving.

Lastly, don't court disaster!  You've attained great results, and any more velociity is superflous, and any more accuracy probably couldn't be taken advantage of with iron sights.  Quit while you're ahead, and safe!

Just my two cents worth!

God Bless,

Marshall
 

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Thanks for your quick reply Marshall. I went out and shot the Cast Performance 335 with 22.2 grains of H110 again today. Groups were not nearly as good. I shot a couple at 50 yards in the 4" range and a couple at 75 yards in the 6" range. Average velocity of 30 shots was 1160 fps and the extreme spread was 75 fps. I think I will go up some more in powder charge. I do not know what to think of the accuracy. Was the 2" group at 55 yards the true accuracy of the load or was the 6" group at 75 yards more realistic? I guess it is much more likely that the 2" group at 55 yards is what the load is capable of and the larger groups were just me not shooting as well. Anyway I did strongly suspect that the 1500 fps measured on Friday was erroneous. 1160 fps makes more sense. I think since I have already tried 22.7 grains and it gave me 40 fps more than 22.2 I will go on up to 23 and 23.5 grains H110 behind the CP 335 and see what I get for velocity and accuracy. Thanks again, Brian C.
 

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revolvers are tough to read by the time u get to the point a mic will read a diff or the primers show u r WAY over 40k psi-- i have found that extraction is the best indicator for the individual revolver
 
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