Seating to crimp groove vs powder charge

[brokeasajoke]

Going by hodgdons online data for Tightgroup, I find I must seat bullets .100 deeper to get the case mouth to the crimp groove. That's a lot less space in the case. Data says 3.2-3.8grs with a coal 1.475. Thoughts? Will I increase pressure too much by seating to groove? I had charged the cases with 3.4gr but I may dump and go 3.2.
304927

[Daekar]

357mag or 38spl?

[brokeasajoke]

357mag or 38spl?

Oops. 38spl.

[Dusty Bannister]

It appears that the data on the Hodgdon site is for a LSWC and you might be loading a RFN cast bullet. Since the bullets are not the same, the crimp groove is not likely in the same location. But this shows why it is suggested that you start at the suggested starting load and work up from there. Are you one to take a chance or are you more likely to set these cartridges aside in a well marked baggie and start at 3.2 gr and see how they do before increasing the charge since you seated the bullet deeper.

[justindad]

Who is the manufacturer of you bullet or mold, and what is the manufacturer’s part number?
*
What is the total length of your bullet?
*
What is your final overall cartridge length?

[Dusty Bannister]

It would be reasonable to measure from the base of the bullet to the lube groove and determine if the case volume is the same if seated to the crimp groove. However, the book data will not show that. So back to start at the beginning and work up as safety indicates. The book data establishes what was used to develop the safe limits and are intended to be a guide.

[brokeasajoke]

It appears that the data on the Hodgdon site is for a LSWC and you might be loading a RFN cast bullet. Since the bullets are not the same, the crimp groove is not likely in the same location. But this shows why it is suggested that you start at the suggested starting load and work up from there. Are you one to take a chance or are you more likely to set these cartridges aside in a well marked baggie and start at 3.2 gr and see how they do before increasing the charge since you seated the bullet deeper.

Only one made up is the one in pic. And it's seated per suggested oal.

[brokeasajoke]

Who is the manufacturer of you bullet or mold, and what is the manufacturer’s part number?
*
What is the total length of your bullet?
*
What is your final overall cartridge length?

Lee 358-158-RF
Coated length is .635
Have not seated to groove yet but would roughly be 1.375ish to groove

[Dusty Bannister]

Then that makes it a lot easier to begin again. Good luck and see what you can determine and update the thread.

[justindad]

My recommendation is to seat to the OACL shown in a load manual, and taper crimp like a bottom feeder cartridge - maybe someone else will comment if this is or is not a good way to go.
*
The Lyman Cast Bullet Manual (4th Ed) has the Lyman 358665 158 grain RFN bullet seated to an OACL of 1.445”, and the starting & max loads of Titegroup are 2.9-3.3 grains. The Hodgkin data has the bullet approximately 0.030” farther out of the case and the charges are up to 0.5 grains higher. So if you now seat your bullet 0.070” deeper than the Lyman data, you would have to drop the charges even further.
*
Load manuals don’t always agree and I don’t know how long the bullet was that Hodgkin used (I also don’t know how long the Lyman bullet is), so I don’t know how much the pressure would increase if you started at 2.9 grains and seated to the crimp groove - might not make for a good day at the range.

[oley55]

I was going to suggest a Lee collet crimp die because they will crimp anywhere on the bullet, but then I didn't really recall seeing one for 38spl. I searched in the usual places for a 38spl collet crimp die but came up short except for this listing: https://www.cheaperthandirt.com/lee-precision-.357-magnum.38-special-collet-style-factory-crimp-die-steel-90812/FC-734307908133.html

Must be a mis-print because I do not see how it could work on drastically different case lengths. Although I wouldn't be afraid to shorten a 357 collet die to work with 38spl. They are cheap enough that if I screwed it up on my bench grinder I'd just shrug my shoulders and toss it and my idea in the trash can.

[reddog81]

.1" isn't that big of a deal in .38 Special. In 9mm sure, but I wouldn't worry about it here.

When it comes to pressure in pistol cartridges the exact OAL isn't as important as how much of the bullet is seated in the case. For a 148 grn wadcutter 3.3 grains is the max and the entire bullet is seated inside the case. 3.4 grains with the bullet shown will be fine.

[Larry Gibson]

".1" isn't that big of a deal in .38 Special. In 9mm sure, but I wouldn't worry about it here."

Could be famous last words......

I don't know about Titegroup powder in the 38 SPL case as I've not pressure tested that combination. I have, on the other hand, pressure tested 5 gr of Green Dot in the 357 Magnum under the TL358-158-SWC seated to different depths. A change in seating depth of .1 from an oal of 1.582 down to 1.482 result in the average psi going from 23,900 to 32,500. that's an increase of 8,600 psi for that .1" deeper seated bullet. In a 357 Magnum revolver both loads were still "safe". However, in a 38 SPL to be used in a 38 SPL firearm that kind of increase in psi could prove not good.

[uscra112]

Listen to Larry.

What counts is not the OAL but the seating depth, i.e. position of the base of the bullet relative to the case mouth. Ignore OAL entirely, as any spec given is only valid for one specific bullet.

Figure out your seating depth and post it; maybe one of us can help you. Also measure from the base of the bullet to the crimp groove with a caliper and post that.

[brokeasajoke]

3.2gr titegroup seated to groove chronographed 799.2 in my Smith 64 with a 4" bbl. and ejected just fine but it was only one. Base to top of groove is .356. case depth with caliper is .983 or so.
305000
Hodgdon shows 815fps in their data for 3.2 titegroup 158 LSWC

[uscra112]

OK, set up a Quickload model with that data, and the predicted velocity is pretty close to what you got. Calculated pressure is ~12.5k psi, which makes it a fairly mild load. If you're happy, stick with it. You've got about .5 grain headroom if you want to go faster, before you get into the red zone.

[Soundguy]

Oops. 38spl.

That's a big roomy case with a very compact powder. you could seat a full wadcutter and not cause any problems with decreased space.

[uscra112]

Wad cutters seated full depth would require a much smaller powder charge.

I loaded 2.0 grains of Bullseye for my Officers' Model Colt, for a 147 grain full wadcutter seated flush. Titegroup would be the same or 0.1 grains less.

n.b. My most accurate wadcutter load actually seated the bullet about .200" out of the case, which let me go up to 3.0 grains. Same pressure. Had I tried 3 grains with the wadcutter seated flush, I probably would have ruined the gun. QL calculates P=36.6kpsi. That's how sensitive the .38 can be to seating depth.

[Soundguy]

Wad cutters seated full depth would require a much smaller powder charge.

I loaded 2.0 grains of Bullseye for my Officers' Model Colt, for a 147 grain full wadcutter seated flush. Titegroup would be the same or 0.1 grains less.

n.b. My most accurate wadcutter load actually seated the bullet about .200" out of the case, which let me go up to 3.0 grains. Same pressure. Had I tried 3 grains with the wadcutter seated flush, I probably would have ruined the gun. QL calculates P=36.6kpsi. That's how sensitive the .38 can be to seating depth.

I load a 148gr hornady 10208 (hbwc) 2.7 - 3.3 gr. titegroup

Plenty of room.... and that's a straight hodgdon recipe...

[brokeasajoke]

OK, set up a Quickload model with that data, and the predicted velocity is pretty close to what you got. Calculated pressure is ~12.5k psi, which makes it a fairly mild load. If you're happy, stick with it. You've got about .5 grain headroom if you want to go faster, before you get into the red zone.

I'm not after hot rodding the 38spl. I have a 357mag if I want to go faster with the same bullet. These are just plinkers.

[uscra112]

I load a 148gr hornady 10208 (hbwc) 2.7 - 3.3 gr. titegroup

Plenty of room.... and that's a straight hodgdon recipe...

HOLLOW BASE. Totally different animal from a solid wadcutter.

Seated full depth even 2.7 would be a pretty warm load. 3.3 is well up into +P territory - 22kpsi.

[Cast10]

Lyman #4 offers the following for 38 special

Lyman 358665 158gr. Flat Tip/TC bullet
Titegroup 2.9 @ 12,800 cup to 3.3 @ 16,100 cup
COAL 1.445”

Lyman 358311 160gr. RN bullet
Titegroup 3.2 @ 11,100 cup to 3.6 @ 16,200 cup
COAL 1.550”

SAAMI max pressure - 17,000 cup

[Soundguy]

HOLLOW BASE. Totally different animal from a solid wadcutter.

Seated full depth even 2.7 would be a pretty warm load. 3.3 is well up into +P territory - 22kpsi.

Lyman lists a redding #52 wadcutter 148gr..titegroup 2.9 - 3.4

150gr Lyman 358091 titegroup 3.1-3.5 and notes it as most accurate load.. That 358091 is a plain flat base dimple tip FULL wadcutter. 13.6-16k cup

Guess Lyman has no idea what they are doing publishing their own data on their own bullet... Right?

[uscra112]

No idea. I just crunch the numbers. Seating depths make large differences, which is what I was trying to get across.

[downzero]

I would use the crimp groove and back the powder charge down. Keep in mind that load data are based on the bullet they use. If your bullet is different, you need to back down and test it yourself.

[brokeasajoke]

I tested one and got 799fps with 3.2 of titegroup with data showing 815 in their test gun. There is a lot of empty space in the case.

[nvbirdman]

The big question is, what is the difference in the boolits when you measure from the crimp groove to the base?

[1hole]

Going by hodgdons online data for Tightgroup, I find I must seat bullets .100 deeper to get the case mouth to the crimp groove. That's a lot less space in the case.

I believe you're greatly over thinking the issue. IF I crimp at all, I always seat to crimp in the groove for any revolver reloads. Revolver cartridges usually have a much larger powder space and they always have a LOT more "freebore" than autoloader cartridges so they are much less twitchy than autoloader ammo.

Off the top of my head, I don't remember the modest peak pressures for .38 Spec. OR the high pressure 9/10MM rounds but the difference between them is quite high so modest differences in book OAL figures hardly matters for revolver (or .45 ACP) reloads. "Experts" rightly warn us about pressure vs. seating depth of the small, high pressure autoloader cartridges that just don't apply to larger, much lower pressure cartridges.

In fact, in some 55 years of reloading everything that goes BOOM! I've never paid any attention to book seating depth for anything EXCEPT the 9/10MM rounds. I have never seen a hint of excessive pressure from any book powder charge for revolver reloads. That has included a lot of .357 loads in .38 S. cases with cast bullets seated to the factory crimp groove.


Data says 3.2-3.8grs with a coal 1.475. Thoughts? Will I increase pressure too much by seating to groove? I had charged the cases with 3.4gr but I may dump and go 3.2.


I don't believe it's an issue but do it if it makes you more comfortable. But, at 3.4 gr. you're already a bit more than 10% below the maximum book charge. At 3.2 gr. you'll be some 20%+ below max and you might need a range rod to hammer out any bullets that get stuck in the bore! ;)


Birdman, I last looked at NV's Yucca Flat in Feb. of 1962. For a Florida blue-suit boy a long way from home, it was kinda fun to work there for a few earth shaking months but I haven't missed it!

Thank you for your service.

[brokeasajoke]

I believe you're greatly over thinking the issue. IF I crimp at all, I always seat to crimp in the groove for any revolver reloads. Revolver cartridges usually have a much larger powder space and they always have a LOT more "freebore" than autoloader cartridges so they are much less twitchy than autoloader ammo.

Off the top of my head, I don't remember the modest peak pressures for .38 Spec. OR the high pressure 9/10MM rounds but the difference between them is quite high so modest differences in book OAL figures hardly matters for revolver (or .45 ACP) reloads. "Experts" rightly warn us about pressure vs. seating depth of the small, high pressure autoloader cartridges that just don't apply to larger, much lower pressure cartridges.

In fact, in some 55 years of reloading everything that goes BOOM! I've never paid any attention to book seating depth for anything EXCEPT the 9/10MM rounds. I have never seen a hint of excessive pressure from any book powder charge for revolver reloads. That has included a lot of .357 loads in .38 S. cases with cast bullets seated to the factory crimp groove.



I don't believe it's an issue but do it if it makes you more comfortable. But, at 3.4 gr. you're already a bit more than 10% below the maximum book charge. At 3.2 gr. you'll be some 20%+ below max and you might need a range rod to hammer out any bullets that get stuck in the bore! ;)


Birdman, I last looked at NV's Yucca Flat in Feb. of 1962. For a Florida blue-suit boy a long way from home, it was kinda fun to work there for a few earth shaking months but I haven't missed it!

Thank you for your service.

3.2 got me 799fps so I believe I have plenty of room yet to go faster if needed. I may try this in my 6.5in 357 and see what velocity I get.

[reddog81]

People have been using 158 grain cast bullet data and seating into the crimp groove for decades and decades and decades. If someone tells you it's going to be pushing the envelope for .38 Special they might not be up to speed on what's been going on in reloading for like the last 100 years.

[gwpercle]

Deleted Post

[Happy caster]

305107
Is this what you asking? Titegroup 2.8gr. Works out to 50 yards. Don't have a chrono but it feels quite poof. I'm a small guy. And yes, that's a lot of crimp. Personal preference

[Soundguy]

People have been using 158 grain cast bullet data and seating into the crimp groove for decades and decades and decades. If someone tells you it's going to be pushing the envelope for .38 Special they might not be up to speed on what's been going on in reloading for like the last 100 years.

Very much agreed...

[Larry Gibson]

Oh, I'm "up to speed on it" alright because I've measured the psi.

If you have a load, particularly a top end load, and use another bullet, even if the same weight, that seats deeper into the 38 SPL case the psi will be higher. As I've posed a .001 deeper seating can mean 8,000 psi difference. With a top end 38 SPL load that would push the psi up to 25,000+ psi. With a top end +P 38 SPL load it could be 28,000+ psi. That is low end 357 magnum factory psi level.

The question is; by switching bullets of 158 gr and seating to the crimp groove is the bullet seated lower in the case than the load was developed for? There is a plethora of damaged/blown 38 SPL revolvers out there. I've seen enough of them. So, who's to say they weren't damaged due to excessive psi from deep seated bullets? Older RD and SWC 38 SPL bullets had close to the same seating depth to the crimp groove. Many newer, especially custom or individually designed, cast bullets can have much shorter or longer lengths to be seated inside the case. Probably why most all manuals and reloading data sites tell us if we change any components, to drop back the load and work back up. Sound advice.

[reddog81]

What pressure signs do you look for when working up a load in .38 Special?

[Soundguy]

Fortunately lead bullet loads tend to develop much less pressures than jacketed bullet loads..when comparing equal weights and same profiles... Note.. Equal weight and profile lead bullets are usually shorter than jacketed due to lead vs copper weight . this all works towards making lead less pressure than jacketed loads of the same weight and profile. Lastly..most lead bullets have less bearing surface than a jacketed counterpart... Again..lowering pressure... And let's face it.. Lead slides easier down a barrel than copper anyway. This all work together in favor of lower pressure lead shooting.

[1hole]

What pressure signs do you look for when working up a load in .38 Special?

Good question.

I've always believed that reloads for handgun ammo might well blow a barrel off before showing any of the common incipient signs of excess pressure for a rifle. Even hot loads for most magnum revolver reloads are designed for lower pressures than modest rifle ammo.

I have my own pressure rules for MY max rifle loads but for handguns I follow the loading book maker's recommendations. The effective down range differences between book max and loading at the ragged edge of a KABOOM is too small to make much difference in use and lighter loads don't pound my handguns to an early death.

[Larry Gibson]

What pressure signs do you look for when working up a load in .38 Special?

We're not going to get any "pressure signs" at 38 SPL pressure levels. If you do then you are probably above 357 Magnum pressure levels.

However, this is where the chronograph comes in handy. If you're using a different bullet than the manual, then drop back and work up to the same velocity level as the manual load. Not necessarily precisely accurate pressure wise but if all the other components, particularly the powder, then you'll still be within safe pressures.

[justindad]

I remember reading in a load manual (Lyman or Western) that if you do see pressure signs, you are probably WAAAYYY over pressure. That statement may be more true for .38 Special and .45 Colt than it is for .357 Mag and .44 Mag.

[Larry Gibson]

Fortunately lead bullet loads tend to develop much less pressures than jacketed bullet loads..when comparing equal weights and same profiles... Note.. Equal weight and profile lead bullets are usually shorter than jacketed due to lead vs copper weight . this all works towards making lead less pressure than jacketed loads of the same weight and profile. Lastly..most lead bullets have less bearing surface than a jacketed counterpart... Again..lowering pressure... And let's face it.. Lead slides easier down a barrel than copper anyway. This all work together in favor of lower pressure lead shooting.

That was the myth for many, many years. I believed it too because it sounds reasonable. Problem is, it doesn't work out that way in reality. I've spent a lot of time, effort and expense trying to determine, by actually measuring the pressures, that cast/lead bullets give less pressure with the same loads as does jacketed bullets of the same weight, seating depth and bearing surface. I've done this with numerous handgun and rifle cartridges. Best I have come up with as to which will give the greater pressure for a given load is; it depends. What exactly it "depends on" I haven't found a concrete answer for. Thus, based on actual pressure testing that theory is not provable.

If you have any empirical data based on the actual measurement of pressures demonstrating such, I would certainly appreciate seeing it.

[1hole]

That was the myth for many, many years. I believed it too because it sounds reasonable. Problem is, it doesn't work out that way in reality. I've spent a lot of time, effort and expense trying to determine, by actually measuring the pressures, that cast/lead bullets give less pressure with the same loads as does jacketed bullets of the same weight, seating depth and bearing surface. I've done this with numerous handgun and rifle cartridges. Best I have come up with as to which will give the greater pressure for a given load is; it depends. What exactly it "depends on" I haven't found a concrete answer for. Thus, based on actual pressure testing that theory is not provable.

If you have any empirical data based on the actual measurement of pressures demonstrating such, I would certainly appreciate seeing it.

Larry, you've mentioned your interesting pressure experiments several times in the past but I'm puzzled about how you did those tests. I mean, for handgun loads, did you only have a pressure test gun with short throats and tight chambered barrels for everything or did you have some kind of common real world long throat and cylinder gap barrels for revolver loads?

What I'm wondering about, might the very short throats of autoloader test barrels vs. the real world long throats and cylinder gaps of revolvers account for the significant pressure differences you found (or computed?) between shallow vs. deep seated revolver loads?

[Hi-Speed]

We're not going to get any "pressure signs" at 38 SPL pressure levels. If you do then you are probably above 357 Magnum pressure levels.

However, this is where the chronograph comes in handy. If you're using a different bullet than the manual, then drop back and work up to the same velocity level as the manual load. Not necessarily precisely accurate pressure wise but if all the other components, particularly the powder, then you'll still be within safe pressures.

Larry is spot on. This is my practice too and the chronograph is an indispensable tool for this. An example - using Speer 38 Spl +P load data their max load for the 158 gr SWC is 6.0 grs using Power Pistol. I start at 10% below and work up…I’ve had 5.6 grs Power Pistol come close to the Speer 6.0 grs Power Pistol manual load velocity in my revolvers as extrapolated for barrel length…stop there.