Problems with 4756 in 9mm


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JBrady555
August 1, 2014, 12:44 AM
Hello I'm fairly new to reloading and I've been playing with 124gr precision delta hollow points with 4756. I started low and worked up but my problem now is that I'm reaching the upper end of the spectrum but I still have a powderpuff load. Right now I'm at 5.5gr@1.135, which is right on the maximum of most of the sources I've found. IMR does list a 6.3 compressed load but that seems way higher than any of the half dozen other sources I've found. I don't have a chrony so that make proceeding delicate on the upper end. Why is my load like a rabbit fart when I'm hitting the upper end of the data? It occasionally jams and many times wont lock the slide back. Should I maybe decrease oal? Thanks.

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PO2Hammer
August 1, 2014, 01:16 AM
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.

gamestalker
August 1, 2014, 02:56 AM
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

Dudedog
August 1, 2014, 07:09 PM
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?

Potatohead
August 1, 2014, 07:23 PM
I love love love it in 9mm. Let me dig up some of my data.

JBrady555
August 1, 2014, 07:24 PM
That would be great potato head

Potatohead
August 1, 2014, 07:27 PM
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.

JBrady555
August 1, 2014, 07:28 PM
Yea im at 5.5 too. But it cycles the slide slow in my p95

JBrady555
August 1, 2014, 07:30 PM
I must admit though, all my malfunctions occured with my wife. Limp wrist with a already light load?

Potatohead
August 1, 2014, 07:31 PM
Could be.. But I think you're about where you need to be IMO.

JBrady555
August 1, 2014, 07:32 PM
What OAL you running at?

Potatohead
August 1, 2014, 07:41 PM
1.13-1.14".

JBrady555
August 2, 2014, 05:56 PM
Shot my 5.5s at a informal club gssf match today. They functioned fine in my g17c but they had a hard time knocking down the plates. They only fell if i hit the top of the plate. Im gonna try about a half grain below imr's 6.3 compressed load. Maybe around 5.8 to 5.9. As light as 5.5 is i think it will be ok.

Potatohead
August 2, 2014, 06:14 PM
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.

JBrady555
August 2, 2014, 06:17 PM
Ill let you know for sure. If you like 4756 you better get all you can. Its being discontinued this year if not already.

Jim Watson
August 2, 2014, 06:18 PM
Well, get over it, it is being discontinued.

Potatohead
August 2, 2014, 06:18 PM
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:)

JBrady555
August 2, 2014, 06:19 PM
Yea but im sure we can get 8 or 10 pounds before its gone. Maybe on sale at that.

Potatohead
August 2, 2014, 06:46 PM
Oh yea, Jbrady, On Noslers site, I noticed they had 4756 listed as their most accurate load for their 115. Just an fyi.

JBrady555
August 2, 2014, 06:50 PM
Gonna check that now, ive got 200 nosler 115gr hollow points on hand now.

Potatohead
August 2, 2014, 07:13 PM
That's the one. (Hope Im remembering correctly)

eam3clm@att.net
August 2, 2014, 09:32 PM
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.

ArchAngelCD
August 3, 2014, 04:26 AM
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
August 5, 2014, 12:53 AM
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.

ArchAngelCD
August 5, 2014, 02:56 AM
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.
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.

1SOW
August 5, 2014, 03:18 AM
ArchAngelCD +1!

I was surprised when I got my chrono how different my pistol reload readings were from what I believed them to be by 'FEEL' comparisons with commercial ammo.

Primer indications can be misleading. Federals will flatten some with moderate loads. Other harder primers may show nothing with high end+ loads.
Feel isn't reliable with new loads.

JBrady555
August 5, 2014, 10:43 AM
Yea I need a chrony for sure. Maybe I won't push for 6gr. I still feel safe at 5.8, it's half a grain below published data from the powder manufacturer and I'm longer than their oal for the published load.

JBrady555
August 12, 2014, 08:34 PM
UPDATE

I loaded a batch of 124gr Precision Delta HP with 5.9-6.0gr of 4756 @ 1.140. The definitely had more thump but accuracy still left something to be desired in my G17. Primers looked good, no signs of over pressure. That was the end of my 4756, I'll be moving on to power pistol and aa 7.

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