4756

[38superman]

As most Open shooters know, supplies of N105 (which was my preferred powder) have all but dried up.

I am forced to find a suitable substitute and upon Bob's recommendation, my first alternate to try is 4756.

I went to the range today with loads starting at 8.5 grains up thru 9.0.

It was very warm and extraordinarily humid. (Think Burma)

The first 10 shot string of 8.5 came in at roughly 168 power factor and the recoil was milder than expected.

My first thought was "This stuff isn't too bad".

The next string at 8.6 jumped up to about 170 pf.

Interestingly, 8.7 stayed at about the same pf, actually dropping a few fps.

8.8 pushed up to roughly 173 pf and that's as far as I went in this session.

All groups had very consistent velocity in the 10 shots strings.

Only once did it deviate more than about 20 - 25 fps.

The function of the gun and recoil impulse was pretty snappy compared to N105.

You could really feel that this was a faster powder.

Instead of a push, recoil was more of an sharp bump.

Not harder, just quicker.

Primers were a bit flatter than I am used to with some minor cratering.

Not excessive by any means but clearly operating at a higher pressure.

Dot jump / movement is definately greater.

It's going to take a lot of work to get used to it.

I thought that maybe pushing up a few tenths might provide more gas for the comp and smooth things out.

However, at 173 pf there was no sign of that.

Bottom line: this powder is only going to be happy in my gun at the bare edge of major power factor.

Probably ok for practice or a club match but to use it in a chrono match is to risk going minor.

Especially if it is temperature sensative.

I will mark this one down as usable but no where near ideal........ Keep looking.

Tony

Edited to note: bullets are Zero 125 JHP.

Edited July 29, 2007 by 38superman

[HSMITH]

I am surprised the primers showed pressure. I managed to get 9.0 in a 9mm with 115 grain bullets and had no pressure signs at all. It only made 163 pf with the case basically full.

Duh, you must be shooting 124/5 grain bullets......

Try some Silhouette, and Longshot. Most of the Super guys up here are running 124's with 7625 now that they can't get N350, and tell me they really like it.

[Jack Suber]

As most Open shooters know, supplies of N105 (which was my preferred powder) have all but dried up.

I am forced to find a suitable substitute and upon Bob's recommendation, my first alternate to try is 4756.

I went to the range today with loads starting at 8.5 grains up thru 9.0.

It was very warm and extraordinarily humid. (Think Burma)

The first 10 shot string of 8.5 came in at roughly 168 power factor and the recoil was milder than expected.

My first thought was "This stuff isn't too bad".

The next string at 8.6 jumped up to about 170 pf.

Interestingly, 8.7 stayed at about the same pf, actually dropping a few fps.

8.8 pushed up to roughly 173 pf and that's as far as I went in this session.

All groups had very consistent velocity in the 10 shots strings.

Only once did it deviate more than about 20 - 25 fps.

The function of the gun and recoil impulse was pretty snappy compared to N105.

You could really feel that this was a faster powder.

Instead of a push, recoil was more of an sharp bump.

Not harder, just quicker.

Primers were a bit flatter than I am used to with some minor cratering.

Not excessive by any means but clearly operating at a higher pressure.

Dot jump / movement is definately greater.

It's going to take a lot of work to get used to it.

I thought that maybe pushing up a few tenths might provide more gas for the comp and smooth things out.

However, at 173 pf there was no sign of that.

Bottom line: this powder is only going to be happy in my gun at the bare edge of major power factor.

Probably ok for practice or a club match but to use it in a chrono match is to risk going minor.

Especially if it is temperature sensative.

I will mark this one down as usable but no where near ideal........ Keep looking.

Tony

Per Derek's (Millenium Custom) and BJ Norris' advise, I tried the 4756 in my son's gun - he is shooting 124 MGs. I like the load a lot and it seemed softer than the 7625 we were using. Our load really filled the case and you had to be careful indexing on the press because to fast would shake powder out of the case. Though I liked the load, my son did not. He prefers the snappier 7625. He says he can follow the dot better with it. When we were working up loads, we experienced some variances in velocities. However, I figured that was due to powder getting slung out of the cases when they indexed. When I slowed down on my loading, the variances in velocity evenned out.

Edited July 29, 2007 by Jack Suber

[al503]

I noticed that n105 tended to wobble slightly from side to side at 170-171 pf, which is the only pf I tried it at and probably too much gas. It's probably great at 167-168.

I like 4756 at about 168 as the dot goes up very slightly but it goes straight up and back down. The only thing I don't like about 4756 is that it's reverse temp sensitive. I vary the powder drop by about .5 grains from summer to winter and it's hard to keep a consistent pf throughout the year.

[38superman]

I am surprised the primers showed pressure. I managed to get 9.0 in a 9mm with 115 grain bullets and had no pressure signs at all. It only made 163 pf with the case basically full.

Duh, you must be shooting 124/5 grain bullets......

Try some Silhouette, and Longshot. Most of the Super guys up here are running 124's with 7625 now that they can't get N350, and tell me they really like it.

I am avoiding 7625 based on Bob Londrigan's advice that it runs pressures up too high in a Pro Sx.

Bear in mind that this is a shorty and takes a little more powder to get the velocities that you would see in a 5" gun.

That puts you on thin ice with faster powders.

Maybe 4756 would work better with a lighter bullet?

I didn't know that N350 was in short supply.

I'm beginning to wonder if any VV powders will be around in the future.

Makes me wonder if I should even bother with 3N38.

That was going to be my next experiment.

Tony

P.S. Primers did not show excessive pressure, just signs of more pressure than I normally see with N105

Edited July 30, 2007 by 38superman

[Brazos Custom]

Tony,

You should be fine with 4756 to at least 1400 fps. It is going to be hard to compare anything to N105 when you are looking at the primers. N105 is extremely low pressure for a 38 super round - it normally does not flatten primers at all - they are still round. I have been using 4756 for about 6 years now at between 1360 and 1410 fps and have many guns out there shooting the same load and no excessive pressure signs in the guns (which is what is important). By excessive pressure signs in the guns I mean cracked slides, eroded breechfaces, burnt out barrels, cracked comps, etc.

Some info to help evaluating a new load: Recoil Management

[38superman]

Thanks for the insight Bob.

Some folks seem to be misinterpreting my comments about pressure and flattening of primers.

I feel like I need to clarify.

When pressures are excessive, primers can flatten out to the point that there is only hairline separation between the primer and the case head.

In that case, the primer has no round surfaces left and has been swaged into an absolutely flat surface against the breechface.

I never saw that with this powder.

There is some flattening of primers with almost any full power load.

What I was seeing with the 4756 was normal flattening.

I only mentioned it because it was a departure from the pristine round primers that come out of the N105 loads.

Except for the firing pin indention, N105 casings have primers that look just as they did before firing.

I have no quarrel with 4756 based on pressure.

My only complaint is that if you get much past 165 pf, dot movement is all over the place.

Tony

Edited July 30, 2007 by 38superman

[ipscbob]

I am avoiding 7625 based on Bob Londrigan's advice that it runs pressures up too high in a Pro Sx.

Bear in mind that this is a shorty and takes a little more powder to get the velocities that you would see in a 5" gun.

That puts you on thin ice with faster powders.

This is excellent advice. 7625 is on the higher pressure end even in a full length 5" barrel. Pressure signs are not always obvious to those who don't really know what to look for. As has been mentioned already, Try Ramshot Silhouette.

[AZ38super]

I switched from 350 to 4756 and think it shoots about the same for me at a cheaper price and easier to get.

When I get around 1400 to 1410 in my older 5" gun I have no dot movement at all, it was weird to see at first when I was testing different loads.

I run a 124 grain Armscor RN bullet and WSR primers but I am thinking of going to WSP instead.

[XRe]

I get similar impressions out of 4756, actually... When switching to it from another powder, the gun seems erratic, blasty, and seems to palm slap more... Shoot more of the loads - I think you'll find it works out to be a timing issue, more than anything else. After the first 100 or so rounds of active shooting, I get used to it, and things seem to function normally again...

[Patrick Sweeney]

Gee, and I've been using 4756 as a Minor load powder.

[Flexmoney]

Gee, and I've been using 4756 as a Minor load powder.

Sissy.

[38superman]

The way powders are drying up you may be using it for everything soon.

[nhglyn]

I am also an N105 shooter in one of Bob's Pro Sx's but, since I can't get it right now I have been experimenting with VV 3N38 and am pretty happy with that as a substitute. Current 3N38 load is 10.3 grs behind a 125 Zero JHP and WSR primers. That is giving me a pf of about 171 here in July in NH. Only negative I have noticed with the 3N38 so far is that it seems to be a "dirtier" powder than the N105.

[shred]

My Dawson Miniguns work great with 7625 & 125's.. 40K rounds on the 'new' one.

I used to run 4756 in the older one but it was such a pain to load I switched. The shooting effects weren't good enough to counteract that.

[Larry Burchfield]

I've been loading 9.3gr of 4756 in my son's 38super with 124gr Precision Delta or Montana Golds for several years now. The case is quite full and sometimes spills a little powder when my 1050 index's. His gun has a 4 port Shuaman barrel and a 3 or 4 port Dawson comp. It runs about a 171pf but he says it shoots real soft for him.

I'm not the shooter but the loader.

Larry Burchfield

[38superman]

I've been loading 9.3gr of 4756 in my son's 38super with 124gr Precision Delta or Montana Golds for several years now. The case is quite full and sometimes spills a little powder when my 1050 index's. His gun has a 4 port Shuaman barrel and a 3 or 4 port Dawson comp. It runs about a 171pf but he says it shoots real soft for him.

I'm not the shooter but the loader.

Larry Burchfield

9.3 gr seems like a lot to get 171 pf.

8.8 was giving me 173 pf.

This was under extremely warm conditions.

Maybe it will take more powder when the weather cools down.

I understand that 4756 is somewhat temp sensitive.

Tls

Edited August 10, 2007 by 38superman

[XRe]

9.3 gr seems like a lot to get 171 pf.

8.8 was giving me 173 pf.

Realize that the Schuemann barrell has relatively huge ports in it... That makes a big difference. But, in the lot I tested, I only needed 8.5gr (w/ a 125 HAP, so .356" bullet) to get to 171PF... different guns, different barrels, etc... and mine has two more ports than a standard Schuemann hybrid...

[RacerX1166]

I've been loading 9.3gr of 4756 in my son's 38super with 124gr Precision Delta or Montana Golds for several years now. The case is quite full and sometimes spills a little powder when my 1050 index's. His gun has a 4 port Shuaman barrel and a 3 or 4 port Dawson comp. It runs about a 171pf but he says it shoots real soft for him.

I'm not the shooter but the loader.

Larry Burchfield

9.3 gr seems like a lot to get 171 pf.

8.8 was giving me 173 pf.

This was under extremely warm conditions.

Maybe it will take more powder when the weather cools down.

I understand that 4756 is somewhat temp sensitive.

Tls

Tony,

That's not far off of what I'm getting with my Pro Sx. Granted, I had a hard drive crash so all of my load data is gone but I recall 9.2 getting me around 170 or so with a 125g jhp Zero. (probably going with MG now that Zero supply has dried up). Had to get that much just to insure I had a margin because my velocities drop like a stone when the gun is heated up.

Edited August 11, 2007 by RacerX1166

[Larry Burchfield]

My boy's gun has some big ports in it. When I tried AA#7 I had to use close to 11.1 to make major. That's why each gun is different. I may use a heavier crimp than some one else.

Larry

[38superman]

This really illustrates why you can't just take a load for granted no matter what the source.

You have to work them up in your gun.

What can you guys tell me about temp sensitivity?

Al posted that his loads vary by about .5 grains of powder from summer to winter.

I have found that the term "reverse sensitive" means different things to different people.

I would like to have a little clarification about this.

My loads were developed in very warm weather (mid 90's).

When the weather turns colder, will I need more powder or less to maintain the same pf?

Tls

Edited August 11, 2007 by 38superman

[al503]

In my experience, you'll need less.

The colder it is, the more pressure you'll get. ~8.8 in the coldest winter months is just about equal to 9.2 to 9.3 for me in the summer. This is in a supercomp case btw, at 1.245"

[HoMiE]

Can you run SR 4756 in 9x19 at major PF? Or is the case not big enough to hold enough powder?

[Harmon]

you simply cannot cram enough in a case to load 9mm to major with 4756, not 9x19 anyway.

Harmon

[XRe]

4756 is simply far too bulky for 9x19 Major. Heck, my .38 Supercomp major load barely fits in a case (much like N105)

I'll add an additional impression, since I've been running 4756 for a few thousand rounds, now.... This stuff is CLEAN. I thought 7625 was clean... and I thought N350 was clean at old major. 4756, at current major, makes them both look dirty. Seems to be plenty accurate, as well, in my gun (1/2" groups at 45 yards w/ a MG 121, currently).