I am kind of new to reloading and I have a question about using Speer bullets in my .38 Special Revolver, the bullets in question are the Speer 110gr GDHP and the and the 110gr UCHP, the first one measures at around .520 the second one measures at around .477 . To me that is around .040 different, when seating the bullets will not the GDHP seat deeper in the case and cause more pressure than the UCHP.
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.38 Special
- Thread starter Jerrymltn
- Start date
ShootistPRS
New member
Measure the bullets from the base to the crimp groove. They may not seat to the same overall length.
This:To me that is around .040 different, when seating the bullets will not the GDHP seat deeper in the case and cause more pressure than the UCHP.
Measure the bullets from the base to the crimp groove.
Seating depth is what determines internal case volume; and thus, potentially changing peak pressures. So yes, you are correct: A longer bullet seated to the same OAL will yield less internal case volume, and likely increase peak pressure (or more accurately, increases burn rate - which indirectly increases peak pressure).
I have 110gn GDHP SB's (#4009), and I verified that they do indeed measure .520. I don't have UCHP's to measure. The big SB cavity in the nose makes for a longer bullet.
Speer #14 used the same OAL tested at 1.445" for both bullets. The depcition in the book certainly appears to show the cannelure (where you should seat the bullet) higher up the bullet (from the base) on the SB bullet, compared to the UC. BUT YET, Speer shows the same load data for both. Why? I don't know. It's a mystery.
I will say that I have used Speer's max data for the SB's using Power Pistol; AA#5, Bullseye, TiteGroup, and W231/HP38 - all with no trouble (for 38 Special). Since the SB's seat deeper in the case that the UC's, I would trust the same data using the UC's. YMMV.
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For a new reloader, for now concentrate on safe reloads and just use book data. Use the OAL suggested by the bullet manufacturer and don't overthink the process. When a bullet takes up more room in the case, yes pressures can rise (important consideration in high pressure rounds like the 9mm P). Not a problem in the 38 Special. The 38 was originally a black powder and has a huge case capacity, comparatively, and seating depth is not as much of a concern pressure wise.
So, for now, just seat the bullets to the canalure or crimp groove, as I figgered the bullet designer has taken into consideration the amount of bullet below the canalure/groove. I too think those 110 gr. bullets are too light (the lightest I've used were 125 gr cast RNFP) and I like 125 gr jacketed HPs for my
heavy loaded 38 ammo, and I have a mold for a 160 gr. LSWC that works quite well in my 2, 38s and one 357...
So, for now, just seat the bullets to the canalure or crimp groove, as I figgered the bullet designer has taken into consideration the amount of bullet below the canalure/groove. I too think those 110 gr. bullets are too light (the lightest I've used were 125 gr cast RNFP) and I like 125 gr jacketed HPs for my
heavy loaded 38 ammo, and I have a mold for a 160 gr. LSWC that works quite well in my 2, 38s and one 357...
jetinteriorguy
New member
Yup, KISS principle applies here. Seat to the cannelure and work up from the suggested starting load. .38 Sp is about the easiest thing in the world to start reloaders on. What powder are you planning on using? Some are better for learning than others, more forgiving in nature and less likely to cause problems while learning.
Thank you guys for all the info, from the base of the GDHP To the bottom of the canalure crimp groove it is close to .185 and on UCHP it is .145 and like you said Nick the book says that the COAL of the 2 are the same so I was a little nervous about doing them, with such a difference in the canalure grooves. I have a lot of Unique so I was going to do 5.6 gr at the COAL it shows in the book. I think I will try the 125gr bullet next, thanks again guys.
BUT YET, Speer shows the same load data for both. Why? I don't know. It's a mystery.
The answer to your mystery might be that the tiny difference (0.04") in seating depth simply doesn't make any practical difference in that cartridge and pressure range.
Yes, it is true the deeper the bullet seats the smaller the powder volume, and therefore the same amount of powder will show an increase in pressure in the smaller space.
Now, the question is, HOW MUCH, and DOES IT MATTER. and Sometimes, the answer is, it doesn't matter.
Small volume high intensity rounds like the 9mm Luger and .40 S&W are very sensitive to small changes in seating depth. Other rounds are much less so.
IF the loading manual show the same powder charges for two different bullets with different seating depth, the obvious answer is that the difference in seating depth was NOT enough of a factor to require a change to the powder charge.
0.04" might be a big deal in a grenade waiting to happen, like the .40S&W, in the .38Special? I'd be amazed if it made any difference.
Jerrymltn wrote:
...when seating the bullets will not the GDHP seat deeper in the case and cause more pressure than the UCHP.
If you don't adjust the seater stem on your seater die, yes.
First, any time you change bullets, check the OverAll Length (OAL) specified in the manual and expect to have to adjust the seating die to achieve it.
Second, you are correct that seating a bullet deeper does reduce cartridge capacity and will have the effect of increasing chamber pressure. The extent of that increase will depend on the cartridge, the powder charge and the extent of the reduction in volume.
The 38 Special started out as a black powder cartridge that survived the transition to smokeless propellant so the powder changes today can be very tiny. Because of this, the case is very often almost empty even when fully loaded so the increase in pressure from a 0.040 inch reduction may not produce much of an increase in pressure.
In other cartridges, such as 9mm Luger, the Speer manual reports one situation in which bullets seated 0.030 inch deeper more than doubled the chamber pressure, so while the 38 Special is a very forgiving cartridge in this respect, it is best to get into the habit of following published OAL recommendations - and adjusting your dies accordingly - until you have accumulated a couple decades of experience.
jetinteriorguy
New member
From my research 5.6 gr of Unique is pretty much a max load, always always start at a 10% reduction minimum and work your way up. Don't just choose some arbitrary starting point and load em up. I constantly see people posting that they are just going to try a load, no, work up to it or some day something very bad is going to happen. You need to instill good safety habits right from the beginning and adhere to this routine, otherwise not only might you injure yourself, but I may be next to you and get injured as well because of carelessness or sloppy loading habits. My apologies if it seems like I'm ragging on you about this, but I'm just trying to stress the importance of being safe for everyone's sake.
K.I.S.S. For now just seat the bullets to the canalure and roll crimp. Use starting loads from your manual and don't worry about OAL. (I reloaded for a few years, started with 38 Special in '69, and just seated all the bullets to the canalure or crimp groove, didn't measure OAL. Made up a few thousand safe, accurate handloads, no problems.).
mikld wrote:
...just seat the bullets to the canalure and roll crimp.
In general the cannelure has been placed at the point that will correspond to the OAL contained in most manuals. There are exceptions, so checking the manual is always recommended, but then 38 Special tends to be forgiving of those who ignore published guidelines.
Even so, 38 Special is the cartridge I reload that scares me the most. The powder charges are so tiny (say 3.5 or 3.7 grains of some powders) that it is possible to double (or even triple) charge a case and not notice it on visual inspection. This is why I have special steps in my reloading procedures for 38 Special to ensure that I don't overcharge the case.
Having used a single stage press for years and then switching to a Dillon 550b for many more years, it has been demonstrated to my satisfaction that double-loads (or failing to charge a case at all) are more likely to happen when a person is using a single-stage press and charging the cases in a cartridge holding block than when loading with a progressive. Some of us shoot way too much (handgun) to mess with something as inefficient as a single stage press for handgun cartridges.Even so, 38 Special is the cartridge I reload that scares me the most. The powder charges are so tiny (say 3.5 or 3.7 grains of some powders) that it is possible to double (or even triple) charge a case and not notice it on visual inspection. This is why I have special steps in my reloading procedures for 38 Special to ensure that I don't overcharge the case.
I always stress developing safe reloading practices from the very beginning. Every new reloader I've talked to is told to look at the powder charge in every case they are reloading before seating a bullet. I had a squib in 1970 and that taught me to look, every time.
Every bullet I have reloaded was designed by someone that took into consideration how far the bullet enters the case and located the canalure or crimp groove accordingly. Seating to the crimp groove or cannalure is not haphazardly ignoring book data, but can lead to much confusion for a new reloader when he seats to the canalure but the "suggested" OAL is off. How many times have we read questions from new reloaders, "I can't get my OAL and still crimp in the groove?". It is a safe practice to seat to the groove/canalure even if the OAL suggested is different (FWIW, reloading manuals are not exacting formula, but published results from what a lab tech(s) found when he used their listed components on their equipment)...
Every bullet I have reloaded was designed by someone that took into consideration how far the bullet enters the case and located the canalure or crimp groove accordingly. Seating to the crimp groove or cannalure is not haphazardly ignoring book data, but can lead to much confusion for a new reloader when he seats to the canalure but the "suggested" OAL is off. How many times have we read questions from new reloaders, "I can't get my OAL and still crimp in the groove?". It is a safe practice to seat to the groove/canalure even if the OAL suggested is different (FWIW, reloading manuals are not exacting formula, but published results from what a lab tech(s) found when he used their listed components on their equipment)...
A Speer tech told me that because the Gold Dots have an electroplated jacket that is softer than a formed cup jacket, they present lower start pressure and therefore need a little more powder than the conventional jacketed bullet does to reach equal pressure. By sticking it in a little deeper (it's the longer bullet) they may simply be making that up. Even if the two jackets were the same hardness, QuickLOAD says the velocity difference you'd expect on the order of 20-25 fps and the pressure difference is on the order of 5-6%, which is within the limits of what SAAMI allows a single loading to vary. So, even without that softer jacket, the data will be close enough for most practical work with both bullets.
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Also, note that when you look at Alliant's site for Unique loads that their data and Speer's will be the same because they are owned by the same parent company and Alliant does all the pressure testing for the top loads in the Speer manual. But be cautioned that even though they call them "recipes", what Alliant lists are actually maximum loads. Only when you download and read the .PDF file version of their manual do you see them state that they expect you to knock those "recipes" down 10% to establish a starting load that should be safe for all guns. So, 5.2 grains should be your starting load and work up in 0.1 grain increments toward their 5.8 grain maximum. You can generally do that with just one round per step, so you are looking at 7 rounds for workup while watching for pressure signs. Just be sure to tilt the muzzle up enough for the powder to fall back over the primer for each shot. That produces worst case maximum pressure that you might encounter. Stop to eject each case after each test shot to feel for sticky extraction and to examine the brass before moving to the next one. 0.1 grain steps seem small, but 2% of maximum charge weight is a pretty normal test step size when looking for pressure signs. You will want to weigh each charge carefully to get that small. In the end, you really want a load that can move around a couple of tenths without consequence, but the SAAMI standard would allow for that already, based on the way they set up their pressure system with error assumptions.