Shooters Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Any help is appreciated- thought that i was working up my loads for my freedom arms 454 methodically with a chrono and caution but i have been kind of confused by results i obtained this last weekend-- i have worked up to a fairly hot load that was very accurate- 1680fps ,335gr cast performance WLNGC bullets over 30.0gr 296 lit with cci 450 primers---the deviation was 5.00, i can consistantly shoot 2 inch groups with this load and felt it would be my choice for elk and deer this season. the only signs of pressure that i noticed was that i required the ejector rod todrop the cases from the cylinder-- not much -just a push.
well, i had a wild hair and decided to go to 31 gr to see if that was pushing things along and perhaps shrink the 2 inches down (altho thats probably me! im sure this pistol shoots much better than i.)i got a vertical string about 4 inches long on center at 1740 fps, sd of 6.78, but i was floored when i ejected the empties i merely tipped the muzzle up and they slid out on their own- bright and shiny- every one i fired! how is this possible? could the crimp do this? i crimp as a separate operation when i load, and use a pretty substancial crimp- just useing the rcbs seating die with the seater plug removed- the lower velocity loads had a deeper crimp--- can anyone shed light on this for me? when i saw the group and the sd i was planning on staying where i was but the fact that the pressure seemed to be lower has me wondering what to do.
 

·
Registered
Joined
·
1,150 Posts
CJM,

If you watch the load height as you increase the load you will no doubt observe that you have a compressed load. H-110/296 is sensitive to compression. Up to a certain point you will observe a velocity increase with increased loads, but above this point you should observe a reduction in velocity. This is without a doubt the result of poor ignition since the fine-grain powder compacts and leaves very litle airspace to allow the primer flash to penetrate the charge. To a point you are actually improving the progressive nature of the powder but when this level is exceeded the poor ignition takes over.

In short, by compressing these powders you see an effective reduction in their burning rate. Even though the increase to 31 gr. gave increased velocity, a pressure gun would most likely show a reduction in pressure. This would explain the easier extraction.

I have observed this effect with these powders in .45 Colt, .32 H&R, and .357 Mag. They are so close to being the slowest burning powders usable for these cartridges that I doubt it is possible to get in trouble with them and heavy-for-caliber bullets. If anyone has any DIRECT knowledge of high quality guns of these, .44 Mag. or .454 calibers being damaged by an overload I would be interested in hearing about them.
 

·
Registered
Joined
·
1,982 Posts
My load in my FA 10" is 31.5 gr. H110 behind a 355 gr. LBT LWNGC for a velocity of 1691.3 fps. With this load, it burns clean and the cases drop from the cylinder under their own weight. With ligher loads around the 25 gr. to 29 gr. mark, cases have to be forcibly shoved out of the cylinder and they are filthy dirty. The reason they must be shoved out is unburned powder is lodged between the case and the cylinder wall. As the powder charge goes up, the load burns cleaner and all is well. At 32.0 gr., I have no velocity increase over the 31.5 gr. load, accuracy is poorer, and the ES is higher. But, they do fall from the cylinder also. Since Taffin listed 32.0 gr. as max with a 340 gr. bullet, I did not go any higher.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #5
thank you for the info- feel much better about this situation - perhaps that one hole group is only a half a grain away
 

·
Registered
Joined
·
1,168 Posts
cjm
Be happy sounds like you found that loads sweet spot-Atleast you didn't have to beat those cases out so you were not in an overpressure situation. :D Keep working with it and you should get those to group in the right spot-you got to get used to that extra recoil-practice! I found mine with my cast 300 gr load at 30.5 gr 296. :D When I went to 31 gr the group open up to about 5" with 30.5 1625 fps, it's about 1 1/2" at 100 yrds! :D
 
1 - 6 of 6 Posts
Top