Published load data way off?

[brayhaven]

Is it just me, or is the published load data, way outside reality?
Been working on some 44 sp and 38 loads.. using mfr and other published data, I'm getting 25-30% lower velocities. 200 gr cast hp over 6.6 of universal is supposed to be up over 950. I'm barely getting 700 using a 190 cast hp. Same with unique and bullseye. As bad or worse in the 38 sp. even looking at barrel length. (4" in both) something doesn't seem right. Or are the lawyers pushing the caution buttons for people publishing reloading data..
Changed batteries in the chrono. Even shot some rifle and factory loads and it seems to be pretty accurate.
:???:

[Went2kck]

if you powder is old and in high humidity maybe it has degraded and lost some power. Just saying.

[Grmps]

Just a thought, try some fmj and check and see if maybe your Chrono might be off

[Outpost75]

Velocity data taken in a solid pressure test barrel WILL be higher than revolver.

[Bzcraig]

Velocity data taken in a solid pressure test barrel WILL be higher than revolver.

This....

[brayhaven]

Velocity data taken in a solid pressure test barrel WILL be higher than revolver.

Thanks. I had that experience for the 50 years I've been loading (test bbl vs real guns 😊)
But even tried the loads claiming to have been clocked in revolvers with similar bbl length. The Pearce article on the 44 spl, data for instance. Not getting anywhere near the performance from 4" bbl. Hate to just keep jacking up the loads. Trying to get a decent 800 fps knocking around load with light hollow points. Even tried a few of the favorite loads from the CB folks here.
Some of my powder is older, but some is fresh.
I'll check the chronograph again.
Have checked loads that were put together many years ago and seem to have the same performance as when loaded. Never noticed any deterioration in powder that was sealed and stored indoors. Maybe the newer stuff isn't as stable as they used to be?
Thanks for the input.

[buckshotshoey]

Try a version or two of factory loaded rounds through your chrony to see if they are comparable to your reloads. That should show if it's a chronograph problem.

[Paper Puncher]

.22 match ammo is very consistent and is great for checking a chrono

[Shuz]

If the spacing between the skyscreens is not exactly what it should be, you will get false readings.

[white eagle]

what data are you using cast or jacketed

[OS OK]

I had a Smith no.3 in .45 Scofield that had such a wide barrel-cylinder gap you just couldn't make any horsepower with it.
Traded it in on another 1911.

[JonB_in_Glencoe]

Velocity data taken in a solid pressure test barrel WILL be higher than revolver.

This ^^^
As well as, COAL effecting amount of empty case space, compounded by boolit weight and size and style variations.
Add to that, how much you are expanding the case...effecting case tension, as well as crimping or not crimping the case. There are many things you could be unknowingly doing different than the publishers, to get lower velocities.

[Outpost75]

.22 match ammo is very consistent and is great for checking a chrono

This is a sound procedure which anyone can do. I keep a brick of old paper boxed Eley Tenex and shoot a string through my 6-7/8" barrel High Standard Model B every time as an instrument check. The ammunition factories follow a similar calibration procedure with specially-loadad SAAMI "Reference Ammunition" in the respective caliber, in which everyone in the industry fires a round-Robin test procedure, turns in their data and the large sample size is statistically evaluated, the values provided and a procedure used to develop and apply, when necessary a "correction factor" to sample observations which fall outside of the prescribed parameters.

In revolver ammunition some calibers such as .38 Special and .357 magnum are often tested in a two-piece "vented" pressure test barrel, in which the chamber is a separate section, connected in a fixture to maintain a constant 0.008" cylinder gap, which presents conditions similar to a revolver. This procedure was often specified for certain law enforcement ammo made under government contracts, but was not applied universally.

The powder companies testing load data for their products and who like to show an attractively high velocity figure for marketing purposes very commonly use a 6-inch solid test barrel in most calibers as a matter of convenience. Such a barrel can be expected to give a velocity average about 80-100 fps higher than a 4-inch vented test barrel maintained at the conditions which were commonly specified for accepting law enforcement ammunition back in the day when revolvers ruled the world. There is very seldom a contract "requirement" anymore for testing revolver ammunition in the vented barrel, so it is seldom used anymore.

The usual expectation in calibers such as the .38 Special, in standard pressure loads, is that the velocity difference is about 10 fps for each 0.001" change in barrel length from "Mean Assembly Tolerance," which is generally 0.005" in a new revolver before proofing. It is normal that some minimal setback up to 0.001" to occur after proofing and targeting, especially in .357 magnums, so "pass 0.006" in which a 0.005" feeler gage can be inserted completely through the cylinder gap, and the trigger pulled and the cylinder rotated a full revolution without resistance, and "hold 0.006" in which the 0.006" gage can be inserted completely through the cylinder gap, but the cylinder will bind when the trigger is pulled, with the "rear gage" in place. The rear gage being a set of max. cartridge headspace gages.

So you will also see the 0.006" figure given as MAT, the difference being that the 0.005" is for WIP (work in process) and 0.006" for FQA (Final Quality Acceptance).

Therefore it is ALSO very possible that you could have a 2" revolver with cylinder gap of minimum tolerance of 0.003" cylinder gap, which produces higher velocity than a 4" gun having a maximum cylinder gap of 0.0008". Many used guns having seen heavy use will have cylinder end shake exceeding 0.002" and cylinder gap exceeding 0.008" which will give as much as 100 fps lower velocity than a new, tight gun at minimum fit-up specs.

This is why revolvers drive ballisticians NUTS!

[mdi]

Reloading manuals are not hard and fast formula. They are the results of the components used, with the equipment used in a lab with the listed powder charges. Your results will vary. It's surprising when home reloaders' results are identical to published manuals...

[gwpercle]

I see the Lyman Cast Bullet Handbook #4 has 38 special tested in 4 inch barrel universal receiver.
The 44 special is tested in a 4 inch and 7 1/2 inch universal receiver. So the fps are not going to be the same as when fired from a revolver.
Just read the fine print and take those fps with a grain of salt.
The pressure is the number you want to pay attention to, don't go over max.
Gary

[brayhaven]

Try a version or two of factory loaded rounds through your chrony to see if they are comparable to your reloads. That should show if it's a chronograph problem.

Tried that with my 3" beretta 22 (975 fps) and ppk 380 (850 fps). Both seemed about right.

[brayhaven]

Reloading manuals are not hard and fast formula. They are the results of the components used, with the equipment used in a lab with the listed powder charges. Your results will vary. It's surprising when home reloaders' results are identical to published manuals...

Thanks for all the great and thoughtful input. I started reloading in the early 60's, buying components and equipment from Herters. And anywhere else I could find it. Showing my age here :(. And yes, has always had variations in published data, one way or another. Though in the early days we didn't know because we had no way to measure performance of our loads, other than accuracy, trajectory and effectiveness on game.
But those variations were usually a matter of 5% or less, never over 10.
In these 2 guns I'm getting 25-35% under published data (cast and jacketed). Both 4" barrels.
What little experience I've had with powder deterioration in sealed canisters, actually resulted in hotter burning characteristics as the coatings that were used to control burn rate deteriorated or sloughed off.
The older bullseye powder is slightly cooler than the new stuff. Have tried both. I'll be trying a 7.3 grain load of universal over a 200 cast 44 sp. and 4.5 gr over a 145 cast in the 38. Have a 624 6.5" on the way. Will try that one as well. Been using my fly fishing gun. A charter 44 sp. bulldog 4" and my favorite 38, a 4" S&W 67.
Thanks again for all the input!
Greg

[buckshotshoey]

Tried that with my 3" beretta 22 (975 fps) and ppk 380 (850 fps). Both seemed about right.

As long as you got fairly consistent readings, I wouldnt blame the chronograph. As said above, it is probably the test barrel used, or the cylinder gap in your revolver, or most likely a combination of the two.

As long as you are getting consistent velocities out of that revolver, it is what it is. I wouldn't worry about it. Have fun.

[trapper9260]

As for what is stated ,also the reloading data is only a guide.

[crackers]

I can't usually match Hodgdon's ten inch pistol barrel either.

[brayhaven]

As long as you got fairly consistent readings, I wouldnt blame the chronograph. As said above, it is probably the test barrel used, or the cylinder gap in your revolver, or most likely a combination of the two.

As long as you are getting consistent velocities out of that revolver, it is what it is. I wouldn't worry about it. Have fun.

That's about what I've decided, Just keep pouring in the powder til I get what I want... or start at max & work up:roll: I finally got a load over 800 today (barely) that's supposed to be Max and over 1000, 4.9 gr of universal over a 145 cast SWCHP (GT). Shot some factory & other loads over the chrono and it seems to be reading well.
Definitely not cylinder gap on this S&W 67 38 sp.. I was shooting. Checked it today at .0015 slight feel, and very tight at .002".

I know published numbers are just guidelines, but never in over a half century reloading, seen such discrepancies. Tried many source loads recommended by shooters of these calibers, Including people here posting their loads.. This is 2 different guns..
I was just wondering if anyone else is finding that 25-30% under performance..
Thanks again folks!
Greg

[buckshotshoey]

That's about what I've decided, Just keep pouring in the powder til I get what I want... or start at max & work up:roll: I finally got a load over 800 today (barely) that's supposed to be Max and over 1000, 4.9 gr of universal over a 145 cast SWCHP (GT). Shot some factory & other loads over the chrono and it seems to be reading well.
Definitely not cylinder gap on this S&W 67 38 sp.. I was shooting. Checked it today at .0015 slight feel, and very tight at .002".

I know published numbers are just guidelines, but never in over a half century reloading, seen such discrepancies. Tried many source loads recommended by shooters of these calibers, Including people here posting their loads.. This is 2 different guns..
I was just wondering if anyone else is finding that 25-30% under performance..
Thanks again folks!
Greg

I think you are looking at the picture wearing the wrong color eye glasses. Speed shouldn't be the ultimate goal. ACCURACY is the goal. I suppose it depends exactly what you are doing with it.

What powder charge (and boolit choice) groups the best on paper? With my Dads vintage police .38 special, it is in the 800 fps range with a 150 swc. That's all he wants or needs.

I too use Universal. I will post the charge weight when I get home.

[buckshotshoey]

I checked my books, and we settled at 4.4 gr universal. It was the most accurate load from that revolver with that boolit. Speed isn't always everything. Never chronographed the load, but should be around 750 fps.

[brayhaven]

I can't usually match Hodgdon's ten inch pistol barrel either.

I can't even come close to Pearce loads chronographed from his 4.5" revolver ��

[brayhaven]

I think you are looking at the picture wearing the wrong color eye glasses. Speed shouldn't be the ultimate goal. ACCURACY is the goal. I suppose it depends exactly what you are doing with it.

What powder charge (and boolit choice) groups the best on paper? With my Dads vintage police .38 special, it is in the 800 fps range with a 150 swc. That's all he wants or needs.

I too use Universal. I will post the charge weight when I get home.

Thanks, I'd appreciate it. I totally agree that punching paper only needs the most accurate. However, I use both these guns as woods carry to shoot wild hogs. And need a certain minimum performance along with that accuracy. Those critters get somewhat irritated with non-lethal attempts to put them down.
800 is about minimum. The load today would be OK in the 38. Still working on one for the 44 sp. I never cared for the magnums. Look forward to trying yours in it. The 38 is my favorite. And this 67 is my favorite 38.
I carried a S&W 15 combat masterpiece during my tour as a combat advisor to Vietnamese backwoods troops. It broke my heart to turn it in after my tour. Later when I found they started making a stainless version, I grabbed one. Got talked into selling that one, but imported this one from Germany. It will be in my estate ��
That gun saved my bacon a couple times over there.
I'm trying to to work up loads with universal because I have 4 pounds and like the clean burn of it.

[buckshotshoey]

I can now see why you want it a little faster. I would feel a little naked hunting hogs with a .38. How fast do you think a fat man can climb a tree? Just watch me! Lol.

[brayhaven]

I can now see why you want it a little faster. I would feel a little naked hunting hogs with a .38. How fast do you think a fat man can climb a tree? Just watch me! Lol.

Haha, depends on the reason he's climbing it.
I don't usually hun them with the 38, but carry it knocking around the woods and have killed quite a few with it.
That said, it's not the caliber. There's no such thing as a "stopping round". Only stopping shots. As a kid, I hunted hogs for a long time with a Colt Woodsmam, killing 50 or more before folks convinced me that wasn't enough gun.:) But I got close and shot them behind the ear or beteen the eyes.
Last year I was scouting for bow season and a bunch of 50-75 pound "barbecuers" crossed the road in front of me. Couldn't believe I hadn't brought a decent size gun. The only thing I could find was a beretta 21, tip up, pocket 22. I slipped around in front of them and as they fed by, dropped one with the old woodsman shot behind the ear. Great grilling for the game that weekend. :)
But I'm too old to climb trees now.
"Use enough gun" Robert Ruark

[buckshotshoey]

Haha, depends on the reason he's climbing it.
I don't usually hun them with the 38, but carry it knocking around the woods and have killed quite a few with it.
That said, it's not the caliber. There's no such thing as a "stopping round". Only stopping shots. As a kid, I hunted hogs for a long time with a Colt Woodsmam, killing 50 or more before folks convinced me that wasn't enough gun.:) But I got close and shot them behind the ear or beteen the eyes.
Last year I was scouting for bow season and a bunch of 50-75 pound "barbecuers" crossed the road in front of me. Couldn't believe I hadn't brought a decent size gun. The only thing I could find was a beretta 21, tip up, pocket 22. I slipped around in front of them and as they fed by, dropped one with the old woodsman shot behind the ear. Great grilling for the game that weekend. :)
But I'm too old to climb trees now.
"Use enough gun" Robert Ruark
Get a big boar charging ya and I bet you could climb like a squirrel!

[brayhaven]

Get a big boar charging ya and I bet you could climb like a squirrel!

You have that right. 2 years ago I shot a boar with a crossbow. Looked to be a good hit, so I didn't re-cock, and trailed him, expecting him to be dead a few yards in. As I followed the blood trail, he rushed at me from my right, just catching my camo pants leg and slicing the fabric. He stopped about 10 yards out, turned & gnashed his tusks and cutters, which is a prelude to a charge. I reached down and cocked the bow and dropped a bolt in, ducked aside from his charge and shot him through the heart with the point almost touching his ribs. This is a 200# bow. No way I could ever cock it ordinarily without the cocking harness. But I found out under the right circumstance, an old fart can cock one by hand. :).
Later followed the original blood trail to see how he got to the spot he tried to nail me from. Found a pool of blood and then where doubled back around to lay in wait. He had heard me coming and went back on the side of the trail.
Never had one do anything like that. But was talking to the refuge manager later(Lower Suwanee NWR) and he said they had an identical case 2 years prior, that nearly cost a guy his life. The boar had cut the femoral artery and luckily his buddy was there to put a tourniquet on and get him airlifted out.

[fredj338]

Test platform is everything. All barrels are diff, all guns are diff, especially true in revolvers. I have 5 diff 4" 357mags, all produce diff vel with identical loads, one a full 125fps diff. than the rest. Bore dimensions, barrel/cyl gap, chamber throat size, smoothness of everything, it all comes into play with pressures & velocities.

[brayhaven]

Test platform is everything. All barrels are diff, all guns are diff, especially true in revolvers. I have 5 diff 4" 357mags, all produce diff vel with identical loads, one a full 125fps diff. than the rest. Bore dimensions, barrel/cyl gap, chamber throat size, smoothness of everything, it all comes into play with pressures & velocities.

Of course you're right, and I've seen that for many decades of reloading. But the max I've seen is about that 10% difference extreme in your 357's. I'm getting 3 times the discrepancy from loads supposedly chrono'd in 4" revolvers. (Mine is 4") Was wondering if everyone understates things for Liability:).

[Bama]

Is it just me, or is the published load data, way outside reality?
Been working on some 44 sp and 38 loads.. using mfr and other published data, I'm getting 25-30% lower velocities. 200 gr cast hp over 6.6 of universal is supposed to be up over 950. I'm barely getting 700 using a 190 cast hp. Same with unique and bullseye. As bad or worse in the 38 sp. even looking at barrel length. (4" in both) something doesn't seem right. Or are the lawyers pushing the caution buttons for people publishing reloading data..
Changed batteries in the chrono. Even shot some rifle and factory loads and it seems to be pretty accurate.
:???:

I have a similar issue with PCed 6mm and 308 cast rifle bullets. they run 150 to 350 fps faster than max velocities listed in manuals for jacketed bullets. Chrono seems to check out with if jaceted rounds are used. About decided the PC is just that much slicker.