Help with SR4756 124gr JHP

[kdhill]

My friend got some SR4756 powder (all he could find) and I am trying to help him develope a load using it and MG 124gr JHP, for shooting in USPSA in production.

On IMR's web site it says starting point of 4.9gr to 5.4gr max. I loaded up some with 4.8gr, 5.0 gr, 5.1gr and 5.2 gr hoping to get around 133ish PF. I chrono'd 10 rounds of each, and was not very pleased with the results. The FPS were not very consistant and did not come out where I figured they would, so dont know if my chrono was giving me bad numbers, but have not really had an issue with it in the past. I loaded them with a COL of 1.135 and a light crimp. Here are my results.

4.8gr - avg vel 958, es 136, sd 50

5.0gr - avg vel 963, es 215, sd 66

5.1gr - avg vel 1018, es 78, sd 30

5.2gr - avg vel 1019, es 159, sd 51

As you can see the numbers were all over the place. Where my HP-38 load 4.2 gr - avg vel 1077, es 79, sd 29, I ran before had more stable velocities.

So I checked my old Modern Reloading manual and for 4756 with a 124gr bullet it has a starting point of 5.7 and a max of 6.2. This is a huge difference from IMR's web site. I loaded up some rounds with 5.4gr, 5.6gr and 5.8gr, but I have not shot them yet, but I am a bit nervous about it since it is over what is listed on the web site. I have done some searching but have not been able to find much data.

Any help would be appricated. I use a Hornady progressive press, and I spot checked the powder weight using a RCBS electronic scale.

Thanks

Kelly

[danman00]

I have not loaded 9mm yet with SR4756 but I have in .40 and it works great. And as far as Hodgden's site, I've found their published loads to be extremely weak for the IMR brands of powder. In some instances, thier starting load wouldn't even cycle the slide of my stock as a rock Glock. Personally I would trust your printed load data over Hodgden's website. Just don't jump the gun too quickly (pun intended). Work your way up slowly.Just my 2 cents.

Edited April 28, 2014 by danman00

[pbcaster45]

Hodgdon data is pretty weak on some of the Winchester powders too...

Edited April 29, 2014 by pbcaster45

[dkelly27]

I had trouble with the gun cycling when i used 5.4 gr. of 4756 so i went to my old data and now use 5.8 grs. and it works great. I shoot a Star Ultrastar 9mm and a Kahr CW9 in 9mm. I have been using 124 gr. Ranier Flat point plated bullets for years.

[Steve RA]

Looks like the numbers for the 5.1 load are as good as the HP-38 load ???

[RH45]

I'm on my 4th or 5th can of 4756, and each lot number chronos different, but, I've never tried it for minor. I use it in .38 Supercomp major.

[7mmb]

Hodgdon's data with Hodgdon powders is weak too, until you get to H110/296, they don't dumb down that!

Hornady maxes out at 5.5gr of 4756 with 124gr bullets, jacketed AND lead. Sierra maxes at 6.0gr with their 125gr and 130gr bullets. Some old IMR data has 4756 maxing out at 6.3gr with a 124gr FMJ.

I just worked up a load with 124gr Xtreme RNs and 4756. I always use jacketed data with their plated bullets because that's what they recommended to me over the phone. I didn't run them over the chrono, just on paper looking for accuracy. I started at 4.5gr and they barely cycled my Witness Match. I stopped at 5.5gr and found a very, very accurate load. I won't be doing any further work up with this powder.

Chrono results don't tell the whole story and can sometimes be misleading. I had given up on Universal in 9mm because of poor chrono results. When I worked up the 4756 loads I also tested a couple of Universal loads on paper for the first time and accuracy was excellent, despite what my chrono had told me about the stuff earlier. I've also had very good chrono results with a 45 Colt load I was working up but on paper it couldn't even hold minute of pie plate at 15 yards. The chrono certainly has its place but results on target is where the real proof is.

[RDA]

I've also had very good chrono results with a 45 Colt load I was working up but on paper it couldn't even hold minute of pie plate at 15 yards.

I guess that would be MOPP...I like that, I might have to use that some day.

[chopps]

I loaded some today at 5.2 grains and 1.165 and was happy with the outcome.

Also loaded some at 5.5 which were ok to I was just more accurate with the 5.2 ones.

[3djedi]

I use 5.2g @1.12oal out of my glock34.

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