I'm trying to work up the most flat shooting and accurate 10mm load for hunting with my G40. I've searched the forums and can't find specific information with the powders I'm using so I thought I'd see if anybody else had some experience with it.

I'm loading up Barnes 140 grain TAC-XP solid copper hollow point with brand new Starline brass and longshot powder (Win LP primers).  I've worked my loads up from a very moderate 8.2gr (1250fps) moving two grains at a time and just tested 9.8gr (1329fps) with no obvious signs of pressure problems (see pic of 9.8 below).  chronographing each round, then checking the primers for flattening, and using a micrometer on the pressure ridge with the notion that 0.443 or less is OK but 0.444 indicates excessive pressure.  I've been checking each brass piece as I shoot. So far I have not exceeded 0.443 on the pressure ridge and no obvious/excessive flattening of the primers (anyone disagree?). I can't find a published safe maximum for a longshot powder and this bullet and the folks at Barnes can only tell me they haven't experimented with this powder yet.  Surely someone has played around with the upper end of this powder bullet combination in 10mm.   I'd like to keep going up but would like some advie from someone who has been there.   I also see PowerPistol and 800-X producing some good velocities so I'd be interested in information about those alternatives.  Also note there doesn't seem to be much difference in velocity between 8.2 and 9.8gr of Longshot.

If you're more comfortable discussing off line email me: Cervidnut(at)aol.com

Thanks, JIM


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Seems to me that Hodgdon's max with a 180 grain bullet is 9.5 grains, so you ought to be fine with a 140 grain and 9.8 grains of Longshot. Shoot safe.


Edit to add: Have a look at https://docs.google.com/spreadsheets/d/1gex6ItGeWQunVZR9B14mseacyEGoreRRrBEXZavfciM/edit#gid=4

It looks like Underwood uses 11.8 grains Longshot with a 140 grain bullet.

I have worked with pure copper bullets in the past but not this particular combination (or even in 10mm).  So rather than advice I'll just offer some things to think about.

While the 140gr Barnes bullet is longer than a similar weight lead bullet, it is still light.  Look on Hodgon's reloading website and you won't see Longshot recommended for this bullet weight.  That has been my personal experience as well.  So at the very least you'll need excellent ignition (maybe a mag primer) and excellent bullet resistance leaving the case.  That has more to do with neck tension than crimp BTW. 

I think you can get decent performance with the 140 gr Barnes bullet and Longshot.  My point is you probably won't get optimum performance.... and to some degree this is opening a giant can of worms and includes an aftermarket barrel.

But back to your point.  I've never loaded 800X but have a lot of history of Power Pistol and CFE Pistol.  My guess is PP will give you much more of what you are looking for than Longshot with this bullet.  There are probably a half dozen equally good powders out there but PP is what I use most with lighter bullets.  But pure copper bullets do not necessarily share internal ballistics with jacketed or pure lead bullets.  It's not a good or bad thing.  Just a different thing. 

I think you are progressing well.  Step by step.  Record and share your findings and enjoy the trip.

Excellent info (especially the spreadsheet) - thank you.  Slayer1, that is what I was thinking -- that I am still in the safe zone for 180gr bullets so I may be well below max for the 140gr.

I have had this nagging feeling that I need to stop with the Longshot and start over with Powerpistol because of the data I've seen and Spudmeister confirmed it.  I think I'll do that. I'm probably not going to an aftermarket barrel on this gun. 

No one is talking about recoil springs - should I be thinking about an extra power spring in my G40?  This can't be good for my Vortex Venom.

This may not be of interest, but here's what I did so far with no pressure signs (probably considerably below max).  Only 3 rounds each.

Powder     gr      bul. wt.    type           COAL        primer      Gun (G40)  Vel Range         ave. Velocity
Longshot   9.6   140   Barnes TAC-XP   1.255   WLP      Glockzla   1248-1347   1299
Longshot   9.7   140   Barnes TAC-XP   1.255   WLP      Glockzla   1298-1368   1335
Longshot   9.8   140   Barnes TAC-XP   1.255   WLP      Glockzla   1296-1368   1329



Thanks, JIM

I shoot a gen 3 G20 and it seems to need a heavier than factory spring for the very hot loads.  Plus it's very easy to do on a Gen 3.  The Gen 4 G20 and G40 use the same double recoil spring.  I don't think many people feel the need to put heavier springs in the gen 4 G20.  I don't own one so it's just an impression.  But... take the G40, add a few more ounces in the slide and it's got plenty of spring IMO.  The G40 does not throw the brass near as far and seems to have a lower slide velocity than a G20. 

Opinions and needs vary but I believe the G40 is ideal for hot loads (especially with some aftermarket barrels).  It is also known to not feed lighter loads as readily as a G20. 

Good luck in your project. 

Deernut, what's the length difference between the Barnes 140s you're using and the 180s that you're basing your max charge assumptions on? I am assuming the 140s are longer. My concern would be internal case volume and inadvertently making a compressed load, particularly if you try 800X.

Good luck with this and thanks for sharing your data.

Barnes TAC-XP bullet lengths
125grain = 0.622"
140grain = 0.682"
155grain = 0.732"

Thanks Shadow.

I just measured a 180gr XTP, 180gr RMR FMJ, and a 180Gr Magtech FMJ. They were .622, .603, and .615. So the 140gr TAC-XP is a little longer, .04" to .079" depending. Not that big of a concern during a workup, as long as you're watching for signs of over pressure. Much bigger difference with the 155gr TAC-XP.

Sorry I didn't see these last 2 replies until now.  The case volume issue is something I didn't think about even though now I do remember some talk about the copper bullets being longer (because of lower density) and thus lowering case volume.  That is a good point and may result in higher pressures at lower loads.  I'm proceeding cautiously.

My 180gr is an RMR 180gr FMJ (flat point) that measures 0.600 long.   The longer 155gr was part of the reason I went with 140gr.

I purchased some PowerPistol and tried a few loads today.  Barnes lists the safe range from 8.2-9.2 for the 140gr TAC-XP .400 10mm
PowerPistol   8.9gr   140gr   Barnes TAC-XP   1.25COAL   WLPrimers  Range=1347-1352   Ave.=1350   n=3
PowerPistol   9.2            140   Barnes TAC-XP   1.25   WLP                                   1291-1355   1314        n=3
PowerPistol   9.4            140   Barnes TAC-XP   1.25   WLP                                   1314-1417   1374      n=3
PowerPistol   9.6            140   Barnes TAC-XP   1.25   WLP                                                      1419          n=1
All of these cases were measured with a micrometer and none had a pressure ridge larger than 0.4325 and I don't think primers are excessively flattened but I welcome second opinions (see pics).  I have no experience with Glocks and the primer hits look odd, but I'm not sure if that is problematic.


Also I was interested in whether LONGSHOT was temperature sensitive so I chrono'ed some rounds with RNR plated 180gr bullets that were stored in the fridge and some that were set out in the sun on a steel box in the sun in 90 degrees ambient temp (ammo was hot to the touch).  All rounds had 9.2gr LONGSHOT - 5 shots of each
Longshot   9.2 COLD   180   RNR Plated    1.26 COAL    WLP   (range) 1258-1296fps   ave. 1277fpos
Longshot   9.2 HOT   180   RNR Plated    1.26   COAL        WLP   (range) 1222-1302fps   ave. 1260fps
Not much difference

Note: be careful, i am talking about 2 different powders in the above message.

JIM




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Good morning Dearnut,

The primers look good.  And yes, Glock firing pins kinda gouge the primers instead of leaving a nice round hole.  Not a problem though.

I have no idea what your max charge if Power Point is but when pressures really get high you will start to get "Glock smiles" with OEM barrels.  I've gotten them with some hot loaded factory ammo so the presence of a Glock smile is not necessarily dangerous but it is certainly not good if you plan to reload the brass.  Going to an aftermarket barrel usually eliminates the smiles. 

You seem to be getting good velocities with the Power Point.  Thank you for passing along the data.  BTW... the longer bullet is not always bad.  Depending on the situation a longer bullet can help fill the case ahead of the powder.  That can help powder ignition and accuracy.  Not always but a 90-100% fill (rather than air) is usually a good thing.  One of the challenges in reloading is taking all these generalities and applying them to your specific loads.  It is a worthy challenge as I have made so many mistakes.

Last night I loaded more rounds at 9.8gr PowerPistol, 10.0, and 10.2.  It will be at least a week or 2 before I am at the range again.  I have noticed with these that I am close to compressing the load - probably not yet but close.  I'm not sure how people calculate that a load is 110% compressed for example.  The only "smiles" I've seen are on my face when I feel this recoil!


I'm guessing at the crimp - just going by sight and feel.  I've reloaded .45 and 9mm for 20-30 years and I know what its supposed to look/feel like.  I could mic it but its hard to measure accurately.  With solid copper bullets it might be different and I'm afraid to crimp too tightly.

Also note that previously I mentioned shooting "hot" and "cold" PLATED bullets to test for temperature sensitivity.  I did that just to test the temperature issue and get rid of the plated bullets.  The plated bullets were sent to me by mistake and they don't shoot well at 1200+ fps.  Those bullets only kept 6 of 16 rounds on a man-sized target with a red dot off a bench at 15yds.  I'm lucky I still have a chrono.  Too fast for plated bullets and RNR sent me the jacketed ones I ordered (I thought the plating was some sort of new cheap FMJ because I had no experience with plated or jacketed after shooting Moly lead for years).

JIM

Update:

Today I tested 9.8, 10.0, and 10.2gr of Power Pistol with a 140gr Barnes TAC-XP hollowpoint loaded to 1.255 COAL (2 rounds) and 1.260 (the rest).  New Starline brass out of a Glock 40 (6" bbl)

PowerPistol   9.8gr   140   Barnes TAC-XP   1.255 COAL WLPrimer      1378-1404 (Vel. Range)   1391   (Average) 194.7 (Powerfactor)    601.4 (Kinetic Energy ft.lbs.)
PowerPistol   9.8           140   Barnes TAC-XP   1.26              WLP         1417-1455                   1436                   201.0                        641.0
PowerPistol   10           140   Barnes TAC-XP   1.26              WLP         1431-1469                   1452                    203.3                       655.3
PowerPistol   10.2           140   Barnes TAC-XP   1.26              WLP                                                 1456                    203.8                        658.9

The higher velocity with 9.8gr Powerpistol in the 1.255 COAL loads compared to the 1.260 COAL loads must be a fluke.  If anything velocity would be higher in a compressed load I would think (and that is not much difference).

No Glock smiles on the brass yet, no flattened primer, micrometer on the pressure ridge of the brass just above the extractor groove measures no more than 0.433 on any brass.

Onward and upward.

Obligatory disclaimer: These loads will probably blow your gun up so start low and work your way up as I am doing.

JIM

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Out to the range again today to push Powerpistol farther (up to 10.8gr) in my G40 (6").  Still no flattened primers or Glock smiles and Starline brass not expanded more than 0.433 just above the extractor groove.  10.8gr still seems very safe, but I don't understand the plateau in velocity between 10-10.8gr.  Makes no sense to me, but every thing is the same except for the powder amount and that is being hand measured one at a time on a digital scale for each round.  How can I stay within 1452-1468 as I climb through 10-10.8gr with lower velocity for 10.6-10.8gr than 10.4gr.  The case volume is nearly full or slight compressed.


Powder              gr powder    gr bullett and type          COAL Primer       fps Range          fps average   number rounds
PowerPistol   9.8              140   Barnes TAC-XP   1.26   WLP      1417-1455   1436                        2
PowerPistol   10              140   Barnes TAC-XP   1.26   WLP      1431-1469   1452                         3
PowerPistol   10.2              140   Barnes TAC-XP   1.26   WLP                              1456                           1
PowerPistol   10.4              140   Barnes TAC-XP   1.26   WLP      1450-1486   1468                          4
PowerPistol   10.6              140   Barnes TAC-XP   1.26   WLP      1450-1522   1458                           4
PowerPistol   10.8              140   Barnes TAC-XP   1.26   WLP                         1457                         1

Well one of the scariest documentations I did and posted was the Buffalo Bore 155 grain using Power Pistol that was so compressed I had to rake it out of the casing after I pullet the bullet out!

http://10mm-firearms.com/factory-10mm-ammo-pull-downs/buffalo-bore-barnes-155gr-tac-xp-pull-down/msg20358/#msg20358

That link is interesting because I don't have a feel for how high (fps) I can go so I am  proceeding cautiously, but it is time consuming and I have to order more expensive bullets.  I went with a 140gr over the 155gr specifically because I heard about the problems with case capacity.  I never did the math to see if 155gr bullet at 1500fps (out of a 6") is more killing energy than 140gr at 1600.  I'm operating on the premise that energy is mass x velocity squared so having velocity is more important.  If you can send a 155gr at 1500fps in safe SAAMI specs then I'm optimistic I'm on the right track and will max out at my next trip to the range with the 10.8, 11.0, 11.2, 11.4 I loaded last night.  Maybe I should make a 11.6 and 11.8.      

I wondered why the Buffalo Bore was only loaded to 1.238" COAL.  Why not 1.260" -- that functions perfectly in my G40 (Barnes TAC-XP 140gr).


Thanks, JIM