IMR 4756 and IMR 4759 - What are they good for?

[kelbro]

I found unopened pounds of both of these powders in my cabinet. I can't, for the life of me, remember what I bought them for.

I'm sure that it was something that I read on here or castboolits that prompted the purchase.

Can anybody shed some light on their uses of either or both of these powders?

Thanks!

 

[Russt]

Not sure what you have to use them in but I use 4759 for reduced loads in my 45/70, also reduced loads in most jacketed bullet cartridges. I use 4756 in cast 9mm & 38spl. I favor it in the 9mm w/cast because it was the last powder I tried when experimenting w/a leading problem. It stopped the problem. Other powders I tried before 4756 include, 231, bullseye, tightgroup, & red dot. I tried PB also and got no leading. I have more 4756 on hand so I use it the most. Just going from memory I think it's around Unique's burn rate but I'd have to look it up to be sure.

 

[wrench]

SR4759 is a great powder for reduced loads in rifle cartridges with jacketed bullets.
SR4756 gets a lot of use as a pistol powder, it's also a great cast bullet powder for reduced loads in rifles.

 

[gamestalker]

Back in the 80's I used the SR4756 for 9mm and it performed very well. As for the SR4759, I don't remember if I ever tried that one, but I think I may have. I'll check my log books and see if I have ever used that SR4759, and how it performed, ect. But definitely SR4756 was what I started out using for my G17 loads.

GS

 

[gamestalker]

SR4759 is a bulky single base powder originally intended as a magnum wheel gun powder, it's rather slow burning in this respect. But apparently it works very well for reduced loads in bottle neck cartridges as well.
And as yet, I can't find that at any time I have ever used it personally. But SR4756 has a broad number of handgun cartridges it works in.

GS

 

[kelbro]

Thanks!

 

[Mobuck]

Check your reloading manuals. Those normally have powders and their general useage.

 

[artee]

I've also used SR 4759 as a reduced load in .30-06. I've used very few cast bullets in these, usually of a fairly light weight (110-135 grain area) to conserve lead. Used a lot of M2 150gn pulls (M2 FMJs) with it. In the area of 24 to 26 grains it seems to match what the SAME charges of Herc/Aliant 2400 do for velocity and accuracy. A good load with one has turned out to be a good load with the other. It's a bit bulkier than the 2400, but not enough to significantly reduce the unused volume. You still have about half the case empty.

SR 4756 was known as the "single base Unique". It is very similar in burning rate and application to Unique. I'm not surprised it reduced the leading as it should have a cooler flame temperature.

 

[Jim Watson]

SR4759 was THE primo reduced load rifle powder until AA5744 and Trail Boss came along.
It still has a lot of good points.

I don't know what SR4756 was originally meant for but it kind of languished as a small gauge shotshell powder until discovered for pistols. It is the LOAD powder for the ultra hot .38 Specials in Speer #8, disavowed by the company but popular with members of the S&W board.
It has some use in IPSC racegun loading, a cheaper substitute for one or another Vihtavuori powder.

 

[kelbro]

Thanks. Looking back through some of my notes, I might have purchased the 4759 for 25-20 loads or cast bullet loads for 30-06.

The 4756 was most likely for 45 Colt.

 

[kerreckt]

I have used 4756 to load 44special. It was some that was given to me and I was looking for a good use. It worked well with my 44special. About 7.5gr. behind a 205gr. bullet, as I recall.

 

[kelbro]

Yep, it could have also been for my 44 Special.

 

[Walkalong]

IMR-4756 is very position sensitive in big cases.

IMR-4759 was designed for reduced rifle loads. It can be used in .44 Mag, but tends to leave some unburned powder. AA5744 is the more modern equivalent. (Do not interchange data, just similar application powders).

You can load any medium to large rifle caliber to three basic levels these days.

100% load density with Trailboss (Powder Puff)

Medium loads with SR-4759 or AA-5744)

Full power with your favorite propellant.

And for some calibers, H4895 will do in between SR-4759/AA-5744 and full power.

 

[savanahsdad]

hey thanks for this thred , I was thinking I was the only one that finds stuff in my gun room and says "whats this for " tooooo funny.. last month I was looking for some cast 44 SWC's all sold out , none to be found a week or too later I was cleaning off some shelves and found a unopened box of laser-cast 44 SWC and I too have powders that I don't remember what I got them for , it will come too me when I need it

 

[Tolkachi Robotnik]

SR 4756 uses

Heavy hunting loads for shotguns, 10 gauge and 16 gauge, are one SR 4756 use. It has a slow buildup of pressure compared to many other powders. Such shotshells pattern well.

As above mentioned, many pistol loads.

Pleased to see some information in this thread posted above.

 

[Peter M. Eick]

4756 makes great 38 super, 38/44's and is ok at 357 Magnum.

I don't use it for anything else, but 100% of my 38 Super loads are 4756 and about 90% of my 38/44's are 4756.

I don't use 4759. I feel the risk of picking the wrong powder is too high for so similar of names.

 

[PO2Hammer]

I use 4756 for mid range (1,000 fps) loads with plated or jacketed 158 grain bullets in the .357.
No unburned powder and no soot, about as clean shooting as it gets. Use standard primers.

 

[beatledog7]

I like 4756 in .40S&W with 180-grain and heavier bullets and in .44SPL.

 

[bluetopper]

I've always thought the numbers of IMR powders were too confusing. I like names for powders much better than numbers.........but they never asked me.

 

[FROGO207]

The IMR numbers were sometimes confusing for sure but they COLOR CODED the containers also. I always look for the correct color label as well as the number on the canisters these days. Did like the old cans lots better as far as ID goes.

 

[Peter M. Eick]

This is why I only allow 4756 in the house. 4759 can never enter my place as the risk is too high. There are so many good powders, I chose one over the other. If I were doing a bunch of 38/55's instead of 38/44's I would have banished 4756 and kept 4759 instead.

The reason 4756 works great in the Super or the 38/44 is they are nearly full case loads. 90%+ powder density so no issues with the charge floating in the case.

 

[HighExpert]

I also discovered a single pound of SR-4759 but it was at the LGS and since they had nothing else that would vaguely work for .223, I bought it. It makes a fairly decent load using the following .223 Rem 55gr JHP 16.5gr SR4759. I don't know much about accuracy yet, but it does go bang runs the gun just fine.

 

[ReloaderFred]

I can't count the number of pounds of SR4756 I've burned over the years in full power .38 Special and 9 x 19 rounds under cast bullets. It's an excellent powder for those uses that gets very little attention these days.

Whenever I'm asked about 4756, my answer is always "it's good stuff for .38's and 9's, with cast bullets".

Hope this helps.

Fred

 

[kelbro]

I'll try the 4756 in 38 Spl. I did find what I bought the 4759 for, reduced 270 loads. Well, I already sold the 270s...