Comparing 3 loads

[mikerjf]

Interesting range trip yesterday. I tried 3 different 357 loads for recoil... each string I loaded one round of each load, so it was literally a shot-to-shot direct comparison.

All 158g coated LSWC. Velocities are not measured, just what the source data said to expect from similar barrel lengths.

Bullseye, 6.5g, 1320 fps
Unique, 6.8g, 1295 fps
2400, 13.5g, 1200 fps

The Bullseye and Unique felt quite similar, but the 2400 had way more recoil. Using the formula calculation, the 2400 load does show it should be more recoil, I guess because of the increased powder weight?

Question: Given same gun, same bullet, does more recoil mean I was actually getting more velocity - no matter what the source data says?

 

[rockquarry]

Interesting range trip yesterday. I tried 3 different 357 loads for recoil... each string I loaded one round of each load, so it was literally a shot-to-shot direct comparison.

All 158g coated LSWC. Velocities are not measured, just what the source data said to expect from similar barrel lengths.

Bullseye, 6.5g, 1320 fps
Unique, 6.8g, 1295 fps
2400, 13.5g, 1200 fps

The Bullseye and Unique felt quite similar, but the 2400 had way more recoil. Using the formula calculation, the 2400 load does show it should be more recoil, I guess because of the increased powder weight?

Question: Given same gun, same bullet, does more recoil mean I was actually getting more velocity - no matter what the source data says?

No, but you have to chronograph the loads to know for sure. Far too many changeable factors involved here. However, if you chronograph enough similar loads in enough guns, you'll get a pretty good feel for what the approximate velocity is, or at least should be.

Test guns for book loads vary a lot; one will use a 4" unvented barrel while another will use a long-barreled revolver and sometimes a 4"-barreled revolver will show the same velocity as a 6" gun.

I'd be more inclined to go with the most accurate load rather than the fastest but it's still handy to know the real velocity from your gun. The least significant factor here would be a recoil formula calculation, but that might be of interest to some.

 

[alwslate]

I don’t know what your data source is but from my own chronograph results the only one of your velocities that is realistic is the load with 2400. Your Bullseye and Unique loads are probably actually in the 1100 FPS range. With more powder you will get slightly more recoil at a given velocity but not a lot. If you used a hot primer your 2400 load would have produced more than1200 FPS so that’s why you felt more recoil.

 

[oldman10mm]

Typically recoil is related to bullet weight, for as the impulse of action/re-action principle. But your bullet weight was the same for all 3.
The 3 powders you used, Bullseye- a very fast powder, Unique- a medium burn rate powder, 2400- a slow powder, I would anticipate the 2400 as the heavier recoil. The Bullseye is being burnt up before the bullet leaves the muzzle and would/should have the smallest muzzle flash, the Unique is being burnt up MOSTLY before the bullet leaves the muzzle, the 2400 is so slow a burn rate that it is still igniting all the way down the barrel and after bullet exit, producing a large flash. That exit burning is probably adding to felt recoil as a 'push'.

 

[jimbo728]

6.5 Bullseye is never what I would load in .38 sp.
Jim

 

[mikerjf]

Both the Bullseye and Unique recipe came from the Alliant Reloaders Guide (2003) that you can get online as a pdf. It shows the velocities mentioned (5.6" barrel) and also shows the two pressures as being an identical 33,900 psi.

(Oh, and we're talkin 357 here, not 38Sp. I would never put this in a 38Sp either, and if I hadn't noticed the published 357 load would never have thought of trying it.)

The 2400 loads in my various sources are all over the map for claimed velocities... I think that one may have originally come from a Skeeter article.

Be nice to have a chrono, but I can just imagine trying to get my range to let me set it up...

 

[OKFC05]

1. Yes, the extra 7 gr of 2400 exits much faster than the bullet MV and is in effect a rocket motor, adding to recoil. Competitors favor powders like titegroup, which generally make required power factor with minimum loads.
2. IMHO, "estimates of MV from similar barrel lengths" are next to worthless compared to a chrono MV in YOUR gun.

 

[Nevada Ed]

You might check that .357 data on the bullseye fps with another manual or two...........

that Bullseye figure, might be 200fps faster than actual loads.........
and it is not the best powder for 158 gr weight bullets if you want high speeds.

 

[Scharfschuetzer]

You are correct in adding the weight of the powder to the total mass of ejecta when figuring recoil.

Still with a 120 fps reduction in velocity for the 2400 load compared to the Bullseye load, your perception of recoil should have be in reverse of what you felt.

As you know, recoil is based on three factors: Weight of ejecta, muzzle velocity and the weight of the firearm.

The difference of 7 grains of powder between Bullseye and 2400 is probably not noticeable, but the 120 fps higher velocity of the Bullseye load should be easily detected as heavier recoil with the Bullseye load. It's simple physics on an empirical scale, but of course humans don't always perceive things in the same way as paper ballistics would predict.

I've always felt that muzzle blast can add to perceived recoil and I think that many shooters react more to muzzle blast than from the actual recoil of a weapon.

 

[alwslate]

2400 is a slow burning powder and requires hot primers for efficient loads. Some handloaders think standard primers are ok for 2400 but velocities are considerably higher with mag primers. In a 4” barreled revolver your 13.5 grs of 2400 might chrono at 1300 FPS with mag primers while your other two loads may be in the 1100 FPS range with the same primers.

 

[Nevada Ed]

Primers are a funny thing, on how they work.

A Mag primer might get higher fps......
but I have rifles and pistols that shoot tighter groups with a standard primer.

I have a custom 30-06 that I shoot 147 to 200 gr bullets out of and it likes
cci standard for light bullets and target work, then accepts all primers for the 165 gr bullets
then with the 180 gr or heavier bullets it wants WLR primers for best accuracy with my 4350 & 4831 powders.

High fps is nice..........
but hitting the target is even better.

 

[rockquarry]

Regarding primers...it may be hard to do considering today's component situation, but rather than take someone's word, shoot some benchrested 25 yard groups in your gun with your load and different primers, standard and magnum. If you have plenty of components, work up a load for each primer rather than just switching primers with the same load like most of us do. Chronograph everything.

Using #2400 powder, I've seen slightly better accuracy with CCI 550 (magnum) v. CCI-500 (standard) in a 6" Python .357, but that may not hold true from one gun to another. Still, it's a good reason to experiment.
Most manuals recommend a standard primer with #2400 and if standard primers are all you have, they're fine.

 

[ReloadforFun]

Powder comprises a surprising contribution to recoil.

For an equal weight gun (39 ounces) the numbers work out thusly;

6.5gr BE@1320fos 7.44 ft-lbs total recoil 5.66 ft-lbs no powder
meaning the powder contributed some 23.9% to the recoil

6.8gr Unique @1295 gives 7.29 ft-lbs total and 5.15 ft-lbs no powder
so the powder contributes 25.2%

13.5gr 2400 @ 1200 fps gives 8.33 ft-lbs total and 4.68 ft-lbs with no powder
meaning the powder contributed 43.9% of the recoil

 

[oldman10mm]

I've always felt that muzzle blast can add to perceived recoil and I think that many shooters react more to muzzle blast than from the actual recoil of a weapon.

Easy to prove/verify. Seems everyone nowadays has a phone or digital camera capable of video recording. Record all 3 to compare recoil/muzzle flip.

 

[mikerjf]

The Bullseye and Unique loads felt similar, really solid but usable recoil level. The 2400 load seemed like lots more kick, startling blast and flash, and made/ripped open a blister on my thumb with the first shot.

Reloadforfun, I should have thought of running the calc like you did - makes it all quite obvious! Amazing.

 

[Nevada Ed]

The Bullseye and Unique loads felt similar, really solid but usable recoil level. The 2400 load seemed like lots more kick, startling blast and flash, and made/ripped open a blister on my thumb with the first shot.

Reloadforfun, I should have thought of running the calc like you did - makes it all quite obvious! Amazing.

Blister...........
maybe invest on a golf glove or light glove to help with that problem?

 

[BLUEDOT37]

Some handloaders think standard primers are ok for 2400 but velocities are considerably higher with mag primers.

Most manuals recommend a standard primer with #2400...

The Speer (CCI/Alliant) Reloading Manuals have been noting for decades to not use magnum primers with their 2400 load data or high pressures will result.

If the manufacturer doesn't know what's best used with it's product who does?

.

 

[alwslate]

The Speer (CCI/Alliant) Reloading Manuals have been noting for decades to not use magnum primers with their 2400 load data or high pressures will result.

If the manufacturer doesn't know what's best used with it's product who does?

.

Clue me in. When did Speer start manufacturing 2400? The actual manufacturer of 2400, Hercules and then Alliant used the Federal 200 SR primer with all loads with ALL powders in their load manuals with .357 loads for “decades”. Lyman has always used magnum primers in all their .357 data for “decades”. My own chronograph results are what I go by and the tall for diameter .357 case shows greatly improved velocity and consistency with 2400 in the .357 with mag primers.

 

[daverich4]

Clue me in. When did Speer start manufacturing 2400? The actual manufacturer of 2400, Hercules and then Alliant used the Federal 200 SR primer with all loads with ALL powders in their load manuals with .357 loads for “decades”. Lyman has always used magnum primers in all their .357 data for “decades”. My own chronograph results are what I go by and the tall for diameter .357 case shows greatly improved velocity and consistency with 2400 in the .357 with mag primers.

That may have been true in the past but this is the current load info from Alliant.

 

[Nevada Ed]

That may have been true in the past but this is the current load info from Alliant.

What the heck is with the 6 & 10 inch barrels !!

They are getting as bad as Hodgdon with data out of barrel lengths
that 75% of us don't have............................

I don't under stand it.