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Old 08-20-2009, 03:12 PM
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Default Load Test - SR-4756 in .45 ACP

After getting good results with SR-4756 in my .40 S&W, I decided to try some loads in my .45 ACP as well. I tested loads with Hornady 230 gr FMJ as well as Missouri Bullet 200 gr LCSWC. The results with the 230 gr were inconsistent and well below the velocities claimed by Hodgdon so i decided to do some more testing with that load. Yesterday a test fired loads ranging from 7.4 to 8.2 grains, using Winchester cases and Winchester LP primers. Velocities were measured at 10 feet and have not been corrected to MV. The results were as follows.

CALIBER FIREARM BULLET WEIGHT POWDER
.45 ACP S&W 1911 MBC LCSWC 200 SR-4756


CHARGE 7.4 L 798.58 H 858.81 A 821.61 SPR 60.2 SD 17.5
CHARGE 7.6 L 827.35 H 921.16 A 866.69 SPR 93.8 SD 28.3
CHARGE 7.8 L 861.74 H 918.71 A 884.05 SPR 56.9 SD 16.1
CHARGE 8.0 L 885.90 H 960.33 A 927.83 SPR 74.4 SD 24.5
CHARGE 8.2 L 935.39 H 993.92 A 964.16 SPR 58.5 SD 16.4

My apologies for the cramped data presentation. I'm trying to figure out how to incorporate an Excel sheet or chart.

Interestingly the Hodgdon data claims 966 fps for the 8.2 gr load while I measured 964 at 10 feet. Testing was cut short by rain but I did get early indications that the 7.8 and 8.0 loads were a bit more accurate. I was very surprised to find both of my forearms as well as the short sleeves of my shirt covered with particles of what appeared to be unburnt powder. The specs were the same size and configuration as unburnt powder except they may have been slightly thinner. Also there seemed to be a good deal more grime in the bore of my pistol. It did clean were easily and there was no leading to speak of so I am generally pleased. I am curious about the unburnt powder and wonder if any of you have run into that with SR4756.

Comments welcome,

Frank
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Old 08-20-2009, 03:22 PM
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You're not loading much more powder under 200-grainers than I load under 240s in my bowling pin loads, which are the only .45 ACP loads in which I use 4756. I'm a big fan of the powder, but it only shines at relatively high pressures, and your unburned powder is a sign of low pressures. I don't offhand recall the exact weight of 4756 I'm putting under my 240gr. lengthened H&G 68s, but it's over 7.5 gr., I believe. I'm running the 240s at about 960 fps. from my Wilson 5 1/2" barrelled comp gun. And no, you won't find that load in anyone's manual. I promise that it is +P or more, so don't go do anything foolish and blame me!
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Old 08-20-2009, 03:29 PM
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Thanks to both of you gents for this information.
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Old 08-20-2009, 09:41 PM
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Exclamation Modern data for SR4756 = unburnt powder in barrel, period.

Frank,
Great report! THANKS!

I haven't used SR4756 behind any of my H&G #68 bullets yet as they are mostly for target (paper punching) loads. No need to hop them up to do that!

I have had the same problem with unburnt powder with SR4756 but only with current data. I found that if I used current data I got lots of unburnt powder and no where near the velocity Hodgdon claims for the same load.

That being said, I really like SR4756 in the 40S&W as I get great velocity with less pressure and since I shoot them in a Glock, that seems like a win/win for me!

I too have a 240gr bullet that I shoot but only out of my revolver. I have a M625JM and I use a load from the Speer #8 to hurl that bullet down range. I can send you the data if you want it. I get over 1100fps out of that 4" tube with them! I would say that is quite a whallop should something get hit with them! Here is what they look like:
(Sorry for the quality of the picture! )


Here is a short video of me shooting the bullets with Elmer Keith's load of 2400:
(Sorry this is just a little off topic!)


At any rate, SR4756 really shines at the top end of the data. It is "Uniqueish" at the lower end, meaning there is a ton of dirt and unburnt powder when used to this end.


Move up to the upper end of the data and things will get better.
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Old 08-21-2009, 12:20 AM
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Frank,

I think that's pretty much what I get with SR 4756.

With 7.0 gr I get an average around 810 fps at 15', using a 230 gr Golden Saber. If I switch to a 255 gr Oregon Trails LSWC, I get an average of 860 fps at 15'.

I also tried 11.0 gr with the 230 gr GS in AR brass for a 5" M625 and got 1105 fps average at 15'. I wouldn't recommend that one for anything other than a M625.
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Old 08-21-2009, 05:27 AM
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Every now and then I see claims that 4756, when loaded above current specs, gives high velocities at lower pressures. Where does the pressure data come from? Not from current loading tables, certainly. Has somebody paid for lab tests? I sometimes wonder about published data. Hodgdon, for instance, publishes data for LilGun indicating impressive velocities at remarkably low pressures. My chronograph tells me, however, that their velocity figures are materially overstated. If I loaded to published velocities would LilGun still provide very low pressures? I doubt it.

Last edited by pinkymingeo; 08-21-2009 at 05:33 AM.
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Old 08-21-2009, 09:40 AM
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Quote:
Originally Posted by pinkymingeo View Post
Every now and then I see claims that 4756, when loaded above current specs, gives high velocities at lower pressures. Where does the pressure data come from? Not from current loading tables, certainly. Has somebody paid for lab tests?

In my testing with SR4756 I relied on the manufacturers data from their website. Hodgdon - The Gun Powder People. I was initially drawn to the numbers for the 40S&W 180 grain loads. I noticed that among all of the Hodgdon offerings, 4756 produced the highest velocity with the lowest pressure. If you check you will find they report 1,018 fps at 28,800 psi for 4756. The highest claimed velocity with the 180 gr load is 1,053 with a pressure of 33,200. It seemed to me that increasing pressure by about 5,000 psi for 35 fps increase in velocity was not desirable.

With my .45 ACP I loaded a 200 gr LCSWC over 8.2 gr of 4756 and clocked an average of 964.2 vs. Hodgdons claimed 966. I think that is pretty close. My cases showed no evidence of excess pressure. There was no apparent blow by and the primers were not flattened or cratered. That would lead me to believe the loads are really not pushing the envelope. I have no reason to test my theory and in fact found the 7.8 and 8.0 loads actually grouped better.

I hope that helps to clarify.

FranK
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Old 08-21-2009, 10:31 AM
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Quote:
Originally Posted by pinkymingeo View Post
Every now and then I see claims that 4756, when loaded above current specs, gives high velocities at lower pressures. Where does the pressure data come from? Not from current loading tables, certainly. Has somebody paid for lab tests? I sometimes wonder about published data. Hodgdon, for instance, publishes data for LilGun indicating impressive velocities at remarkably low pressures. My chronograph tells me, however, that their velocity figures are materially overstated. If I loaded to published velocities would LilGun still provide very low pressures? I doubt it.
pinky,
To answer some of your questions honestly, I don't know. I do know that someone did in fact test SR4756 on two different occasions when we were talking about "THE LOAD" with differing results. One stated that the pressure was tested well above 30,000cup while the other was well under that. More in-line with 25,000cup. Well above current data, no doubt and outside of SAAMI standards for even the most serious of +P ammo.

While this is being discussed, you raise a good question. If I load to the Hodgdon's website data, say for 357mag with 158gr LSWC and I get "XXXX" fps velocity, which is 300fps below what they list, what pressure did I develop to get that velocity?

I think you are of the persuasion, and nothing wrong with taking that line of reasoning, that you had the listed pressure without the listed velocity. Is that right?

I am of the other persuasion, if I didn't get the listed velocity then I didn't have the listed pressure either. Apples to apples for me. I can get within 20fps of what they do when I load for the 40S&W and the same weight bullet within their data. That doesn't hold true when I go to revolver rounds. 38spl or 357mag.

It can be blamed on cylinder gap but in my experience with the 45ACP in both revolver and the 1911 platform it just doesn't hold true. Case in point: 230gr Ranier TMJ with 8.0gr HS-6.
M625JM**********************PT1911
Low 775fps ******************Low 772fps
High 827fps *****************High 833fps
Avg 806fps ******************Avg 796 FPS
ES 52fps ********************ES 60fps
SD 22.24fps *****************SD 17fps

As you can see from that data, I must have had one round in the PT1911 that went a little high while the rest of the rounds seemed to settle in at 790fps or so. I didn't keep a list of each round fired. What you can see though is that the cylinder gap didn't seem to affect the results at all. With a shorter barrel I got the same velocity (basically) from each platform.

It is from tests like this that I have derived my thought process, faulty as it may be!

I hope this helps you to understand my position. Not trying to sway you or anything like that, just to get you to understand, that's all. I think both points are valid, yours and mine. We both have used deductive reasoning to arrive at our conclusions.

If I have a closed system like a bolt action or single shot rifle to test out of I will stay with published data pretty much. I feel I am shooting on the same platform as the data was tested in. When we go to pistol/revolver rounds though, I don't have any single shot firearms to test my loads out of, therefore I go by velocity, within reason!

Again, I hope this helps you understand, not agree, but understand my position.

'Preciate your knowledge and participation on the forum.

Best to you!
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Old 08-21-2009, 10:54 AM
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How does it compare to Power Pistol with heavy bullets and top end loads? I get great results with Power Pistol in both .45 ACP and 9mm revolvers. I find that 231 is also a good powder for 255 gr. cast bullets in .45 ACP. Both SR4756 and Power Pistol are hard to find here at the moment, and my precious pound of SR4756 will for the moment be reserved for the wonder loads in .38 Special.

Dave Sinko
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Old 08-21-2009, 11:47 AM
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Power Pistol is the reason that I haven't yet gotten around to messing with SR 4756 in .45 ACP. It is a very easy powder to deal with, and it gives nice results.

That said, I'd think that 4756 ought to move the heavy bullets out a little better, at the higher end of the pressure levels. I've used 7625 lately with .45s and been real pleased with it, too. And - toward the other end of the .45 burn scale - Green Dot, too.
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Old 08-21-2009, 06:11 PM
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I was really just thinking out loud on the pressure issue. I really don't know, one way or the other. For performance loads in 45 acp with 200gr bullets I use AA7, which gives me right at 1100fps from a 5" revolver at published max. Beats published performance, but I do that from time to time with AA's data. Over pressure? Beats me. Not enough to hurt a 625, for sure.
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