Hi guys. I am about to make some 38special rounds for my 686 Competition. These would be intended for home defense. I chose Hornady 125gr XTP bullets and have Accurate #5 powder.

I am trying to decide what velocity to choose for rounds using Hornady 125 XTP bullets. To get some idea what speed to choose, I looked at a bunch of commercial ammo. That just got me confused because I see a big overlap in speeds for 38sp and 38sp +p

Hornady commercial ammo with that bullet is specified at 900 fps and they call it 38 special. Other brands labeled 38special are closer to 950fps.

When I look up commercial ammo with 125gr JHP bullets labeled as 38special +P, I see speed from 945 to 1200fps.

The load data for #5 with 125gr XTP shows the velocity range for 38spl from 981 to 1080 and +p from 1080 to 1180.

The commercial products have 38spl and +p both around 950fps. The #5 reloading data shows +P at 1080fps or more. I don't understand that. I guess the +P designation is more about pressure and not velocity but I think the average guy buying ammo off the shelf would think +p is a "hotter" load. In most cases, it must just be a faster powder leading to a +p pressure but no greater speed.

This doesn't help me pick a design speed for my XTP bullets. The Hornady product info doesn't say anything about suggested velocity although they do have a video showing a gel test at 900fps. The lowest speed shown for that bullet using #5 powder is 980fps which is hotter than most commercial ammo whether its called +p or not. Confusing!

Hornady has a chart designating acceptable velocities for use.
The Xtp acceptable velocities are anywhere between 800-1600 fps.
I can find it in my Hornady reloading manual.
Its everywhere on the internet as well.
Just google “Xtp velocity chart”

__________________
Romans5:8

Why not just get a box of factory defensive 125 gr .38 Special and then tailor your handloads to match velocity for practice?

Do you have a cronograph?

May I assume you have a chronograph? If so simply use it for load development until you get those Hornady 125's moving at around 1000 fps near the muzzle. Begin with book values for your powder and see what your revolver delivers.

If you do not have a chronograph get one. They are cheap with reliable models starting at around $100 and they are easy to use. Pick up a cheap camera tripod for mounting.

At the risk of preaching to the choir; hand-loading without a chronograph involves guesswork concerning performance and there's simply no need for that. Velocity is your best indicator of approaching the pressure maximums with which you may be uncomfortable. No, it doesn't measure pressure, directly, but is generally your best available method to stay away from excessive pressure - all based on the velocities you're recording versus book data.

One can get some sense of excessive pressure from other indicators such as flattened or punctured primers, or hard extractions, but by the time these may be experienced your past where your chronograph would've likely indicated the need for backing off - or simply no need to go "further."

You should easily be able to achieve 1000 fps with 125 grain projectiles and #5 without excessive pressure.

__________________
Ordnung muss sein
SWHF #789

Turns out the speed range is written on the box which says 700 to 1500. But, the test data on Lucky Gunner shows these bullets barely expand at all with a measured speed of 892fps. The Hornady website has a video which seem to show good spreading at 900fs. Seems doubtful that 8fps would make that much difference.

So that is where I ran into the confusion about 38spl vs 38spl +p. A lot of the commercial +p ammo isn't any faster than the regular 38sp.

My idea was to look up commercial rounds using 125gr JHP bullets and see what speeds the were designed for. It is still unclear how much speed the Hornady bullets need to get good spreading. If they don't spread, I might as well use my cheap 158gr LRN bullets.

I think I will get a chrono but that still doesn't tell me how much speed I need to get good spreading. Results on Lucky Gunner with that bullet at higher 357mag speeds does show good spreading. At just below 900fps, they don't spread much at all.

Since you will be shooting a 686......

I would make sure that copper XTP is going fast enough to expand.

Nothing worse than a JHP that does not open up and acts like a fmj.

A +P load is needed with that bullet's design.

Put a few into six lined up water jugs , to make sure that they perform correctly.

I don't know what Lucky Gunner is, but nothing will take the place of experimenting on your own. You might find it not only enlightening but enjoyable and you'll have your answer.

Your Hornady XTP 125 grain bullets will generally expand as advertised at 1000 fps given "normal" defensive distances. Clothing and anything else encountered can make a difference.

Get 'em moving at 1000 fps, something not difficult to achieve with #5 while avoiding excessive pressure, and you're making about the best effort you can.

By the way; don't believe the velocity info published on boxes of ammo. They didn't use your revolver. Your new chronograph will dramatically demonstrate how optimistic lots of "advertised" velocities printed on boxes of ammo truly are.

__________________
Ordnung muss sein
SWHF #789

Its just a website that sells ammo but the guy makes a lot of videos I have found useful and does a lot of testing. This link is where he tested a bunch of 38speical and 357 Magnum commercial ammo firing into gel blocks.

https://www.luckygunner.com/labs/rev...llistics-test/

I would love to do my own experimenting. I will probably get a chrono but I don't know if my gun club will let me put jugs of water out on the range. I don't have private land where I just go shoot stuff, unfortunately.

Pretty sure ammunition manufacturers for 38 Spl. Ammo will specify ammo and bullet weight/velocity to have POA/POI that will match the zillions of revolvers that DO NOT have adjustable sights.

So, if 38 Special has a specific velocity it will probably have acceptable "precision" at 15 yards. But it also should provide acceptable expansion as well.

When test firing dozens of armory S&W M10 revolvers around 20 years ago using all the variations of ammo we had from Winchester every gun/ammo combination was +/- 1 inch at 15 yards.

I'm would hope Horandy would use the same rule of thumb.

Smiles,

Since your gun is a .357 Magnum, why not just buy a box of just about anyone's factory 125 Gr. JHP ammunition and call it good. Save the handlloading for shooting paper with cast bullets and save a bunch of money!

__________________
Gunsmithing since 1961

If only it was that easy. There is no 357 Mag ammo that I have seen in my area. Big 5, Sportsmen Warehouse, and a Bass Pro... none of them have any. I see some online for about $1.40 and up a round plus shipping and FFL fees.... I can make it for much less.

I have everything I need except the load data says to use SPM primers and those I don't have. Some threads say regular SP primer will work.

Revolver velocities will vary + or - 100 FPS. Without a chrono you will never know. My 4” is slower than both of my 2 1/2” guns with one load.
Have a good Easter.

__________________
Fide Et Amore

The American Gunner ammo from Hornady in this exact caliber and bullet is rated at 900 fps...

Accurate #5 will very easily get you to 1,000 fps: Hodgdon's +P START LOAD of 6.8 gr is 1,074 out of a 7" (and WHY a 7" I'll never know?) barrel.

Load up some starting at 6.0 in +0.2 gr increments and see just how you like them? In your 686 they should be pretty mild & manegable...

Cheers!

P.S. For comparison purposes their Critical Defense with the 125gr FTX bullet is rated at 1,500 fps in 357 Magnum: these would be appropriate for a 686 as well.

Yes, I mentioned this in my opening post. What got me concerned about mimicking that load was the testing shown here
https://www.luckygunner.com/labs/rev...llistics-test/

The 125gr XTP bullet didn't open very well at 892fps. Based on the inputs here and a couple of other palces, I am going to load them in the 357 brass even though I don't have SPM primers.

There's a significant difference as far as anticipated hollowpoint bullet expansion between 892 and 1k fps.

Why would you need (or even consider using?) Small Pistol Magnum primers if you are not using a powder nor a load that requires them? You'll need to use more powder in the longer 357 Magnum cases to develop the same velocities, BTW.

Cheers!

P.S. Another question might be why you would consider an (as in "one") internet test video as somehow being more definitive of performance than Hornady's engineers & designers? Test media is just that: test media.

Why do you need SPM primers for AA#5/125gr bullets in 357mag cases???

The data I have specifies SPM primers. I think I have mentioned this a few times. I understand some people are saying SP primer work fine but nevertheless, the Western Powder V8 load data to AA#5 357 mag is based on mag primers. Here is a screen shot. The setup is at the top and the data for the 125gr XTP is the last line. It says primer Win WSPM.

Attached Images

AA#5 357mag.jpg (101.4 KB, 231 views)

So I went to build some 357 mag loads today and it turns out two years ago when I ordered brass, I either ordered wrong or they sent wrong. I have 357 Max not Mag. So no 357 mags for tomorrow. I punted and made some 38spl +p with 7.1gr; sort of in the middle of the +p range for AA#5.

Anyone want some 357 Max Starline brass?

Good luck finding someone with that cool cartridge, but if you do they should be interested...

Cheers!

P.S. I just reread this thread: when did you switch to wanting to load 357 Magnums? Every reference was to 38 Special and circa 1k fps velocity...

You can always use small rifle primers in a pinch: your L-frame should provide plenty of hammer strike to fire them off.

Getting good XTP expansion at 357 Magnum velocities is a snap!

Unless the mfg explicitly states otherwise in the fine print of the owners manual , fixed sight .38spl revolvers are nominally regulated for 158 gr @ nominal 755fps
( Yeah , yeah , in recent years 130gr fmj is the current dominant " practice ammo" , anf 158 rnl is rare to see on a shelf . But 158 is still the legacy industry standard .)

You're seeing widely different things , because things actually do vary widely
From mfg to mfg , lot to lot from same mfg to mfg , and gun to gun . FWIW , at the tail end of the Revolver Era , mainstream offerings were typically advertised at about 950 fps from 4 inch vented test bbl . In current era , there are several boutique mfgs that have offerings significantly higher .

As .455 Hunter suggests , the only way to comfidently and accurately approach load development seeking to approximate factory offerings , is to chronograph factory loads from Your Gun for a baseline , and develop loads from Your Gun with similar velocity .

I'm not in your area , nor shop in the same stores . but defensive ammo for .38 +P ( and .357mag ) is being made , and is on the market . Not necessarily every offering , from every makers , but a sufficient plentitude of ammo reasonably suitable for intended purposes . If not at your corner store , you might have to visit a large- ish gun show , or order using that newfangled Internet thing . Even if it costs a premium , your not going to be plinking with it . A couple boxes to test to establish baselines , or even to load up for actual Defensive purposes won't break the bank . Use your duplication handloads for practicing or recreation .

As everyone is saying , basic chronographs are cheap , and if you are seeking to develop loads that ( meet a particular velocity goal ) , it's not possible to do so without one .

Sugguested loads for AA-5 ? I dunno . Haven't loaded .38spl with AA-5 . But it's a medium speed powder, with burn rate in same general neighborhood as Unique , and should be able to provide any reasonably plausible velocity level in .38spl .

By all means use what you are comfortable with. If they say mag primers then you know what they tested with. More specifically winchester sp mag primers.

Myself I see the winchester mag primer use as a "blanket" statement. They also used mag primers with:
AA#2 which burns faster then clays
zip which is their version of WW231
Solo 1000 which is their version of bullseye
AA#5 which is their version of power pistol.

Clays, ww231, bullseye & power pistol don't need mag primers. But yet most 357mag data lists the use of mag primers for testing simply because it's a lot easier to print the use of 1 primer
vs multiple primers for the same bullet/load.

At the end of the day you'll get more variance in the velocities of your reloads by shooting them muzzle up then muzzle down over a chronogrph then using a standard sp primer with that 125gr/AA#5/375mag load.

I'm pretty sure somebody would be willing to trade you .357 Magnum brass for .357 Maximum. That cartridge has seen a bit of a resurgence since some states that were previously shotgun-only for deer now allow straight wall cased rifle ammo.

While you're on the right track, you need to take listed velocities with a grain of salt. There's a lot of variables that can cause widespread variations in results. Even if you found data using your exact load with your exact model of gun there can still be a lot of variation. Without a chronograph you'll need to guess on the high side.

Never heard of anyone loading by "velocity" before, as most handliaders now, and through the years didn't have chronies. Don't get too wrapped up in speed Bud, although most of those new to reloading do, it's not a true measure of a cartridges effectiveness. You do know the most effective weight bullet for 38/357 is 158gr? Stick with Factory 158gr JHp/JSP for SD, you're loads will never match those for SD needs.

IMHO the 110 gr hollow point is the way to go in 38 Special.

This comes from varmint hunting with a 4 inch barrel. At 1100 fps expansion works well at close range, out to 25 yards or a bit more.

With the 125 gr JHP, I upped the velocity in the 357 load to 1300 fps for longer range with a scoped M19 6 incher. This load killed varmints at 100 yards DRT.

I have been excoriated a number of times for saying I test all my carry ammo on varmints. But I know what kind of wounds my ammo makes.
When you are protecting your family, you need the right tools.

Well I didn't know that 158gr is the most effective weight. I did do some research before buying the 125 XTP's although not exhaustive. I looked on several ammo company websites to see what they were selling for ammo designed for defense. It just seemed like the 125gr weight was pretty common. I'd be happy to buy commercial ammo but don't like to pay gouging prices and there is not much availability. Being in Cali and near the metro area, there are not many stores nearby that sell ammo at all. Since I was already set up for 38spl and 357, I figured I might as well make some for the time being.

Maybe the velocity thing is from my trap background. I mostly shoot trap and velocity is a big deal there. The rules specify maximum velocity for each load weight.

I ordered a ProChrono last night

Remember the 95gr JHP Remington load/bullets....?

I'd never advise to go beyond published data - BUT, guess what? It's been done carefully by experienced loaders who know how to look for pressure signs, and for a very long time.
I've been loading .38 Spl. and .38 Spl +P for longer that I care to think about. In fact, I can date myself by stating Unique and 2400 have been my go-to for many years for upper level .38 loads.
The OP says he's loading for a very modern M686 .357.
That platform provides a LOT of 'wiggle room' in what and how you load .38 ammo.

I enjoy loading for a c.1950's .38-44 HD with ammo duplicating the original .38 'Hi-Speed' ammo with hardcast 158/160 gr. LSWC's.
Doubt you'll find much modern loading manual data for that - and I restrict it to that gun and various .357's only. Never the first issue or problem.
Were I to own a M686, I'd not worry about going well into upper-level .38 Spl. loads.

__________________
Ret'd LEO
SWCA #2275

When reloading the different types of Hornady bullets, one must know....

that the XTP & the FTX act differently at the fps that they are fired at.

Make sure that you know and learn, how these two types of bullets,
perform in your guns, if used for SD work.

The XTP needs a minimum of 960fps to get 98% results, to expand.

In a 38 snub nose the Remington GS at only 877fps is 100% with a .67 dia expansion.

Know what your ammo will do, in your revolvers.

So this is great. Exactly the kind of info I needed: the speed required to get full expansion. However, my question now is where did your numbers come from? I didn't see that number (960) on the box of bullets, nor on the website. Did it come from independent testing or is it published somewhere. I would much rather be able to look up this info than have to ask in the forums for each bullet type. Same question for the GS bullets. Where can I find the data?

Did a search for GS bullets. I don't think Remington is making them anymore.

Try searching this forum for a while... It may answer some of your questions.

Question #1: "Full expansion", but, in what media, with which firearm, with what barrel length...?

Questions #2, 3 & 4: Where and how do you expect to have this information presented to you? Via the box or the website? Published by whom for what purpose?

Not sure why this is so difficult. What do I expect? I expect the manufacturer to provide performance data about their bullets.

In my professional life, I am an electrical engineer. I design and build complex electronic equipment. I have to choose components and I rely on all kinds of detailed data from the component manufacturers. For the most part, the manufactures provide a "technical datasheet" that usually has what I need.

To me, a bullet is just another component and is used to build cartridges. Hollow point bullets are pretty obviously designed to operate in a certain manner in a certain media. My understanding is that ballistic gel is the standard media for evaluating performance. I do not see any technical datasheet on the Hornady website. The fact that guys like Chris at Luckygunner feel like they need to exhaustive testing on their own kind of speaks to fact that the manufacturers do not publish much data. There is no doubt that such data exists. Whoever designed the XTP bullet at Hornady had some set of requirements to drive the design and certainly performed tests to show the design met the requirements.

If Hornady and other companies are going to sell bullets, I don't think it is asking too much for them to provide detailed technical performance data in whatever form they chose to validate their design.

The Rem GS was from a factory ammo box that I had to buy.......
The XTP was a reload that was tested with six powders & my chrony.
I also had a 125 Gold Dot fail to even start to open up in my snub nose J frame revolver,
one reason you should test all ammo in "Your gun" to see what happens.

The 38 110 gr is the lightest JHP that I would ever use with the
125 gr GS in 3rd place and the 135 G Dot in 2nd place.
For my M49, the best bullet/load for accuracy & POA, plus low recoil
and maximum expansion and 12" penetration in a lot of test in Gel, (net)
and my 32 target & chrony test loads made me a beleiver in the......

Federal HST, 130 gr Micro load for 38 snub nose revolvers.

These test are due to the recoil that I can work with and place shots on target
and reach a fps that will let the bullet work correctly at ten feet.

As a note;
I did my last bullet penetration/expansion test on 8/12/2012.

With todays quality bullets, you just need enough fps.......
Tight groups.

Well, for the reloading component bullets they tell you the weight, the diameter the ballistic coefficient and the various Features... No exposed lead, controlled expansion, cannelure on some, etc.

They have a chart that list expected velocity ranges for expansion.

After that, from a reloading standpoint at least(?), you are on your own.

YOUR results may, indeed, vary. Considerably, and not necessarily better than the factory loaded product in all cases. Upon occasion one finds improvement. That's kind of what reloading is all about...

Any expectations regarding "detailed performance technical data" may exceed that which they feel necessary to release. Take a look at the information they provide for their factory loaded product (ammunition), and in this case (Hornady) their loading manual if you feel you need and deserve more. Note they don't mention which powder (or powders?) they use, among other things.

What obligation do you feel they have to release their proprietary design and manufacturing data in order to "validate their design"? Validate to whom?

Cheers!

P.S. Before the internet, how many people ever even heard of ballistic gel?

Do you have the link for that?
I did some more searching and found this
https://press.hornady.com/assets/pct...tics-Chart.pdf

It doesn't mention expansion at all. On the last page, it has information I already knew: that the 38spl American Gunner cartridge with the 125gr XTP bullet has a muzzle velocity of 900fps with a 4" barrel. That is consistent with the video I already mentioned that is on the Hornady website showing that bullet entering ballistic gel at 900fps.

The problem is that I have any number of posts here and elsewhere telling me I need more velocity. Nevada Ed posted that one needs 960fps to get 98% expansion. I asked where that number came from which is a fair question. Also, like it or not there are the tests posted on Luckygunner showing poor expansion performance at 892fps (measured entrance speed).

All of which brings me back to my original question. How much speed to I need and what is the source of the data.

I see now that Hornady has a reloading app and a book. I'd buy those things if I knew for sure they contained expansion vs velocity data (in ballistic gel).

Nope. The chart basically shows a bar graph with velocity ranges for different XTP bullets. Just google XTP chart or the like...

You may be making this more difficult and technical than needs be...

You have an L-frame that will shoot 38 Specials through 357 Magnums. You have 125gr XTP bullets and Accurate #5 powder. Western powders has extensive load data for 38 Special, +P & 357 Magnum loads for this bullet.

If 900 fps from the factory in 38 Special causes you some concern from an expansion & self defense standpoint, just load 'em up a bit faster.

Can be done in 38 Special brass, in 357 Magnum brass, with regular or magnum sp primers, or with small rifle primers in a pinch.

Ed's numbers come from his years of past experience. Take them for what you will. He's indicating that in his experience & opinion one needs around 1K to get 98% reliable expansion with that bullet. One might get there in a carbine length barrel easier than in a 2 1/2 " Model 19. He's not telling you what powder and how much. How YOU get there depends on you: your gun, your powder, your reloading expertise.

Cheers!

P.S. At some higher velocity levels other problems may arise, like bullet fragmentation, etc. Very much like prunes: are two too few, are three too many?

Not everything is as cut and dried as you seem to expect: barrels vary, powders vary, chronographs vary, scales vary. Testing media varies a lot! Maybe you should consider doing all the testing and research needed to generate this "expansion vs. velocity data (in ballistic gel)" you desire and for possible publication? Who do you plan to approach to validate your data and conclusions?

Regular SP primers will work fine in applications calling for magnum primers.

Only the bad guys that attempt home invasion

Simply looking to build effective HD rounds.

I shot some 38spl rounds yesterday loaded with 7.1gr of AA#5. They certainly went bang. That is supposed to be a medium +p load. Have to wait until my Prochrono arrives to get any actual data.

I am trading my mistakenly bought 357Max brass for 357mag brass. I will try that too when I get it.

Make sure you hit 'em 1st: shot placement is REALLY what it's all about!

Cheers!

P.S. The Hornady load data for that load out of a 4" barrel is not even in what THEY consider to be in the +P range: they show somewhere between 850 and 900 fps, with 7.6 gr at 950 fps and +P designation.

Western Powders load data shows, as you stated, 7.1 gr being mid- +P, between 6.8 gr @ 1,074 and 7.5gr @ 1,184. But, this out of a 7.7" barrel: almost twice as long.

Who ya' gonna' believe? I've loaded many hundreds of 125gr plated FP bullets at loads between 6.4 and 7.4 gr of #5 and they all went BANG! and slaughtered the targets (paper, NRA) with nary a hitch.

Hornady doesn't show #5 in their 357 Magnum data: Western starts off with 9.6 gr @ 1,273 fps. Those will most certainly expand. Factory American Gunner 125gr XTPs in 357 Magnum show the same 1,500 fps I previously mentioned in their Critical Defense line. Want to bet they used the same powder?

Personally I would not hesitate to add a bit more to the +P load OR load less than the START load in 357 Magnum cases: it's all up to how much MORE BANG! you feel you need to make you happy for your proposed HD application.

P.,P.,S. Happily, your L-frame will handle them with no sweat. And, if you REALLY want to go higher, the HODGDONS websight shows a 21.5 gr load of WIN 296 with this bullet @ OVER 1,900 fps!

I wanna add another view, since it hasn't come up.

While one shouldn't believe everything one reads on the innernet, there are some loads repeatedly mentioned as being effective by those with "street cred". (LEO's, long-time reloading bloggers, county medical examiners, etc.)

Your 125g JHP is one of those mentioned... in a 357, going about 1400 fps.

38 Special? You are usually going to hear about the FBI load, a 158g soft lead hollow-point going what, 900ish? The soft lead helps expansion at the low velocity.

I think what I'm saying is that, given you have a 357 revolver, trying to make the 125g JHP into a 38 Special load is not what a lot of guys with street experience would suggest.

I think, based on everything posted here, I had pretty much come to the same conclusion. I was going to build 357's over the weekend except for two things: I thought I needed SPM primers and then it turned out what I thought was 357 mag was actually 357Max. Once I get some 357 brass i can build some 357's. Turns out I found some CCI SOM primers and I have Federal WP primers. I can try some loads with both primers and by that time I will have my Chrono. I still won't know anything about expansion.

BTW, earlier today I emailed Hornady and asked them if them had more "terminal ballistics data" for the 125XTP bullet, specially spreading vs speed. They actually replied within a few hours and here is what they said:

"Thank you for your email. The XTP's you are going to be using the those cartridges will open up at a velocity under the 900fps. That typically is the minimum recommended muzzle velocity."

So despite a lot of discussion here to the contrary, Hornady is still claiming 900fps.

Is a 158gr soft lead HP bullet a product I can buy? Any suggestions?

The Buffalo Bore FBI load is well-liked, and the bullet they use is available from Rim Rock. That would be a good place to start, particularly since Buffalo Bore advertises “real world” velocities from various firearms.

"I'm in pure disgrace at the reloading place...
'Cause my XTPs won't expand!"

(With apologies to Charlie Drake, Sir George Martin and the entire Aboriginal race!)

(But none to the UK's ABC Radio nor the BBC for banning and requiring a lyrics change to be extra squeaky pc!)

Note;
I needed 960fps in my 1.88" J frame snub nose.........

if you have a 4" revolver , it might be tight enough to get 930-950fps, which will work.
I did not see what length your barrel was in the first link.

Hornady ammo is loaded on the light side, so it can be improved
if one thinks it needs it?
However a company should sell SD ammo that will do the job correctly, one would think.
Their bullets are KNOWN for their deep penetration, which some think
is more important than expansion.

Sorry to muddy the water, with my test.

I can see clearly now, the rain is gone... If only my vision underwater was better!

Thought your posts were very inciteful, Ed!

Doubtful there will ever be that perfect bullet, perfect load, perfect result...? We can only try and try again, huh?

Cheers!

I don't think you muddied the water at all. You actually answered my question. I was just curious where your number came from. If is was from your own testing, that's great.

My gun for this is a 686 Competitor which has a 6" barrel.

bit of an update:
I now have a Chrono and will hopefully be testing it out tomrrow with a few loads. I now have 357mag brass and made some low-side 357's with Hornady 125XTP bullets to try (9.7gr of AA#5.)

I also now have those Rim Rock 158gr bullets for the FBI load. They are gas checked but not jacketed.

Here is my question. Since I will be using all this in a 686 Competitor, how would those Rim Rock bullets work out loaded with 357 brass rather than 38spl? A very experienced guy at my club (active LEO) says he loads 357 brass with 38spl levels of powder. Maybe I can find the charge that would give about 1000fps using 357 brass (mimicking the Buffalo Bore load) and it would be better for the gun than running 38spl brass?

"Thank you for your email. The XTP's you are going to be using the those cartridges will open up at a velocity under the 900fps. That typically is the minimum recommended muzzle velocity."

They will open up........
but by how much ?

to .40 dia, to .50 dia. , to match some other SD bullets at .71 dia. ??

Just remember this...........
even a bullet can have a bad day, in performance.........
be it a low fps of a load or even a bad lot, that went through the factory.

Way back when the Speer Gold dot bullet first came out, there was a test
where the bullets fails.
The company sent out new bullets to be tested and they worked.

Sixty years later, I feel a lot better with the SD bullets being produced
but there is always a chance that, that 1% will raise it's ugly head.