Problems with 4756 in 9mm

Since taking over IMR powders, Hodgdon has really taken the steam out of 4756 and 7625 data, so I'm not surprised.

I load 4756 over the current max in .357 magnum which is still below the old starting data.

If it were me I would continue loading higher until my slide cycled properly as long as there are no over pressure signs.

Obviously you do this at your own risk.

I'm certain I used to load with 4756 back in the mid 80's for 9mm, I just can't seem to find the data. I was loading for a G17 and recall that it performed just great. I'll look again in the morning, as I just finished bedding an action, so I'm pretty worn out right now.

GS

I have only used a couple of pounds of 4756 but I have heard rumors it varies lot to lot more than some other powders. I noticed in the 2 lots I had about a .2 gr difference to get the same vel. Just my experience, anybody else found this with 4756?

I love love love it in 9mm. Let me dig up some of my data.

Im at 5.3 and 5.5 for a 124. no problems with it. Maybe your springs? Dunno. Maybe it just "feels" like a bunny fart load. That's one of the reasons I love it in 9. Just a nice little push, instead of a snap. Oh I see now you're getting jams, didnt catch that the first time thru. My OALs would be similar to yours. You could always try to mash em a little shorter though.

Could be.. But I think you're about where you need to be IMO.

1.13-1.14".

Please PM if I dont catch your post and let me know how that works out when you do it. That's my favorite powder. I was hoping it was just a gentle kicker and not a weak load. i would like to see how it works with more powder.

Well, get over it, it is being discontinued.

No doubt, j Brady. my 7625 supply looks much better, I like it too. I wonder how much will be in the pipeline, or how long we usually see a powder after it gets discontinued?

Well, Jim, Im having a little trouble getting over it. Like a girlfriend movin away in high school

Oh yea, Jbrady, On Noslers site, I noticed they had 4756 listed as their most accurate load for their 115. Just an fyi.

That's the one. (Hope Im remembering correctly)

SR4756 was the first powder I ever loaded with. I used it with the heavy 9mm bullets (147 grain). I havent loaded with it in a while, but I seem to remember not being able to get enough of it in a case to cause pressure problems with the lighter bullets. It's not a dense powder and fills the case nicely. Compare your COL with load data for other Hollow point bullets, and the powder charge used. Most times HP bullets are seated deeper and uses a lower powder charge than a round nose profile. It kind of sounds like you have a COL of a round nose bullet and a powder charge of a hollow point bullet. When you are researching load data for an unknown (not listed bullet), compare the COL with the load data. It is ok to go longer because you will have less pressure due to having more case volume, but as you have found out you may have a weak load at that level. Going shorter is a no no because you increase pressure due to less case volume.

I checked some of my books and this is what I came up with,
Hornady #9 lists 5.5 grain max with a COL of 1.060
Lee #2 lists 6.3 grains for Jacketed at a COL of 1.135
Load Books lists 6.3 grains for a 124 grain remington seated at 1.135, 4.9 grains for a sierra FMJ seated at 1.090

I would work my way up to 6 grains and see what happens, or decrease my COL. I like my HP loads to be around 1.100 in 9mm, but I have gone longer and shorter depending on the gun. Varify the above load data and work up your load. Use at your own risk.

The load data on the Hodgdon site is even lower than you are using right now but the OAL they list is also much shorter too.
http://www.hodgdonreloading.com/

You can not tell by feel if a load is too light because some powder just feel lighter. They produce less felt recoil, that's why reloaders like those powder in those cartridges. You really need to run those rounds over a chrono before you go much higher on the charge weights IMO.

The load data from IMR in 2001 listed a 124gr bullet with an OAL of 1.125" and a max charge of SR4756 of 6.3gr C. Funny enough they list the same charge weight for a 115gr bullet too.

The IMR 2004 manual lists the same charge weights with a 124gr Remington MC bullet and an OAL of 1.135" Again, the 115gr bullet load is the same as the 124gr load.

The current load data from Hodgdon lists a 125gr Sierra FMJ bullet and a max charge of only 4.9gr SR4756 but the OAL has been shortened considerably to 1.090". A 124gr Berry's bullet lists a max charge of 5.4gr SR4756 with an OAL of 1.150".

I really think you should try and find someone near you to check the velocity of the rounds you are building. I'm not saying the ammo is too hot, I'm only saying you don't know. I know Hodgdon has neutered all the SR powders load data but unless you know what velocity you are generating you can't know for sure...

JBrady555 said:

Just sized and primed 300 cases to be loaded tomorrow with 4756 and a 124gr projectile. I'm gonna start at 5.8 with a few rounds to check for over pressure signs. The goal will be getting to 6.0gr hopefully with no flattened or cratered primers.

Click to expand...

By the time you see classic pressure signs in a handgun cartridge you have by far exceeded the pressure limits and crossed over into the danger zone. Primers are a very poor indicator of excessive pressure in handgun cartridges.