180 Gr Lead and Longshot

[control_the_trigger]

I like 9.2 gr of Longshot with 180 gr XTP, I saw no pressure signs up to 9.5 gr (didn't go higher).  Is 9.2 safe with 180 lead, has anyone seen pressure differences between lead and XTPs/jacketed and Longshot (physical signs, smiles, bulges, etc.)?  I'm not concerned about leading... I have confidence in the hardness and diameter.  Details below.

I plan on working the load up and looking for pressure, but I'm thinking most of my loads are going to be at 9.0 or 9.2 gr Longshot with 180 gr lead the next session out.  I will make a few at lower and higher charges to see where I am at.  I bought Longshot when I couldn't find other powders, then I scored my other powders for other calibers and I didn't have a need for it.  I got lucky when I got into 10mm, because Longshot seems like my main powder I would like to use for the 10mm currently.

I did a workup with 180 gr XTPs and Longshot in a Glock 20 SF with 22 pound RSA and came to the same conclusion I have read about, 9.2 grains of Longshot seemed pretty good.  My goal is 1200 plus with 180 grain bullets for true 10mm velocity, good accuracy (of course), with a small safety margin, decent brass life, and ability to drop charges (hand weighing not necessary).

I don't have my exact velocities with me right now, but if I recall correctly 8.9 was around 1200fps or slightly lower, 9.2 was around 1230, and 9.5 was getting 1250 plus [that was for Longshot and 180 XTP, edit].  OAL was 1.260 inches.  The added velocity didn't seem worth it to bump up to 9.5 grains for me, I liked the 9.2 for my goals.  Oddly enough the second time testing the rounds was lower velocity then the first on all charges, perhaps because the ammo had cooled down, it was closer to room temp at the beginning and near 40F at the end...

Anyhow I like to stay in book data and PowerPistol wasn't getting good velocity from the book charges Alliant sent me for lead when I chrono'd them, and they didn't feel like 10mm.  Longshot doesn't have book data for lead, anywhere that I have looked.  Hodgdon sucks at emailing me back, I have emailed them twice and haven't heard back, once for 10mm and another time for another caliber.

At this point I am wondering if lead will seal better = more pressure = should go with lesser charge than XTP OR.....

lead has less friction/negligible difference than jacketed = pressure almost the same as jacketed = same charges will work.

Again I will look for pressure signs and work up, just seeing if anyone runs 9.2 grains of Longshot under lead and jacketed as a go to, or drop a little less for lead...

Thanks.

[cwall64]

I am going to follow this closely, I a going to use Longshot also, I think I'll try the Hornady HAP 180gr (ordered a bulk lot of them).

[The_Shadow]

Underwood was claiming 1250 with their 220 HC loading using 8.6 grains
http://10mm-firearms.com/factory-10mm-ammo-pull-downs/underwood-220gr-hard-cast-pull-down/

Double Tap was claiming 1300 with 200 with Gas Check loading 8.2 grains
http://10mm-firearms.com/factory-10mm-ammo-pull-downs/double-tap-200gr-wide-flat-nose-hard-cast-gas-checked/

Only testing will tell

[control_the_trigger]

Underwood was claiming 1250 with their 220 HC loading using 8.6 grains
http://10mm-firearms.com/factory-10mm-ammo-pull-downs/underwood-220gr-hard-cast-pull-down/

Double Tap was claiming 1300 with 200 with Gas Check loading 8.2 grains
http://10mm-firearms.com/factory-10mm-ammo-pull-downs/double-tap-200gr-wide-flat-nose-hard-cast-gas-checked/

Only testing will tell

I might try to test 180 XTP at 8.5, 8.9, 9.2, and 9.5 with XTP and lead and post results.

I am going to follow this closely, I a going to use Longshot also, I think I'll try the Hornady HAP 180gr (ordered a bulk lot of them).

HAPs should be similar/identical to XTPs as far as pressure/velocity/accuracy.  Depending on your goals 9.2 seems great with Longshot and 180 jacketed hornady bullets, obviously be safe and work up.  Some seem to go higher then that if they want nuclear, but my goals are "solid" 10 mm, not nuclear.

[cwall64]

HAPs should be similar/identical to XTPs as far as pressure/velocity/accuracy.  Depending on your goals 9.2 seems great with Longshot and 180 jacketed hornady bullets, obviously be safe and work up.  Some seem to go higher then that if they want nuclear, but my goals are "solid" 10 mm, not nuclear.

That is all I am after too, nice solid round, between the off the selve stuff and Underwood!

[jazzsax8]

I just put a 180gr lead bullet cast by the no longer Friendswood Co across the crony today using Longshot.  The bullet measured .4015 so would not reliably chamber until I shortened the OAL to 2.245.  Fed 150 primer and 8.5gr L.S. went 1199 & 1220fps.  I was using my KKM 4.6" on the G29.

[The_Shadow]

That good info!  Kind of what I expected!

[Pinsnscrews]

180gr Rainier Plated HP
9.6gr (just showing the beginning signs of primer flow) Longshot
1375fps average of 10 shots (borrowed chrony at the range from a curious fellow)
CCI primers
1.26COAL
RIA 2011 model 10mm

Points to note: some of the rounds have not physically made it to a 25yd target before disintigrating. Maybe 1 in 20 or so.

1 squib due to bad primer (barrel full of unbunt powder)

Accuracy to 25 yards is 3inch from a rest.


ETA: 9.6gr of Longshot works in MY gun, it might not work in yours. Please work up to it and check for pressure signs if you choose to load that hot.

[The_Shadow]

Pinsandscrews, I can relate to your findings.  I have stopped at 9.2 grains - 9.4 grains of LongShot for the 200 grain real jacketed bullets and 9.6 grains for the 180 real jacketed bullets, I just don't see any advantages to driving them any faster especially with the pistols.
I have seen the plated rounds shed their plating when driven too fast.  Not all plated bullets are the same quality either.  Many also tumble due to poor stability because of the platings being stripped by exceeding the bonds.  This can destroy the accuracy even inside of 25 yards...

[Pinsnscrews]

heh, I was trying for 9.5gr but the Lee powder measure disc dropped EXACTLY 9.6 grains every time. Made a test batch, the RIA sucked it up like candy, so I loaded 400 rounds before I realised the disintigration problem. I do have the occasional range brass piece showing over pressure signs, but a quick glance at the headstamp and it shows it being Privi brass that I missed in the cull 

[eph411]

I appreciate all the info fellas. I had back surgery earlier this week, so I'm spending my down time reading up on load data for the 10mm. I've got a few thousand 180 grain Montanan Gold JHP and about 5 lbs of Longshot waiting for me on the bench, so this info is exactly what I needed!


Eric

[Pablo]

Awesome thread. Need to put the 10mm turret on and go to town. Have 180gr bullets and Longshot and clean cases and large pistol primers. WOOT.

[Taterhead]

180gr Rainier Plated HP
9.6gr (just showing the beginning signs of primer flow) Longshot
1375fps average of 10 shots (borrowed chrony at the range from a curious fellow)
CCI primers
1.26COAL
RIA 2011 model 10mm

Points to note: some of the rounds have not physically made it to a 25yd target before disintigrating. Maybe 1 in 20 or so.

1 squib due to bad primer (barrel full of unbunt powder)

Accuracy to 25 yards is 3inch from a rest.


ETA: 9.6gr of Longshot works in MY gun, it might not work in yours. Please work up to it and check for pressure signs if you choose to load that hot.

I have seen this quite a bit when playing with plated bullets. Rather than disintegrating, they are likely tumbling and bending like a Frisbee because the copper is compromised in an asymmetrical way.

In my testing, velocities approaching 1100 fps got too hot for plated bullets, and crimping any more than just barely closing up the case mouth also caused problems. Berry's and Rainier say to keep below 1300 fps, but that is way too optimistic in my experience.

At distances like 25-30 yards I'd see a couple of good target strikes, then "where'd that go?" Unfortunately one time it happened on the clock at an IDPA classifier one time during the infamous stage 3. Embarrassing score.

I eventually did manage to get reliable groups (good not excellent) with plated bullets after I came to grips with what I was dealing with. That was by keeping velocities mellow, giving a generous case mouth bell, seating and crimping in separate steps, and only crimping enough to barely close up the case mouth. I guess you could say it was pretty boring fodder for the 10mm, but fine for gamer loads for IDPA and so forth.

[Pinsnscrews]

Both Rainier and Berry's have moved the velocity down to 1250fps btw.

Thin copper plate and soft lead core, at 1300+fps in a 1:16 twist barrel is a pretty hefty RPM. There is a guy on the Cast Boolits forum who has a very interesting study into the "RPM Threshold" and how it adversely effects cast bullets. It is very possible, the bullets are spinning themselves apart. Any imbalance in a soft core like that is going to magnify that imbalance even more at higher velocities. 1375fps for a bullet that was not meant to go above 1250fps(realistically 900-1050fps since it is meant for a .40sw) is a big jump.

[Taterhead]

Both Rainier and Berry's have moved the velocity down to 1250fps btw.

Thin copper plate and soft lead core, at 1300+fps in a 1:16 twist barrel is a pretty hefty RPM. There is a guy on the Cast Boolits forum who has a very interesting study into the "RPM Threshold" and how it adversely effects cast bullets. It is very possible, the bullets are spinning themselves apart. Any imbalance in a soft core like that is going to magnify that imbalance even more at higher velocities. 1375fps for a bullet that was not meant to go above 1250fps(realistically 900-1050fps since it is meant for a .40sw) is a big jump.

A soft hollow point varmint bullet shot from a 22-250 at 4000 fps can come apart. Swaged lead not going to rip apart at service caliber velocities and twist. lead is frequently shot from carbines under much more abusive conditions than a service pistol can bring. I have reproduced the precise conditions that you describe where a plated bullet seems to vanish.. Almost certainly, if you were to move the target distance in by 10 yards, you'd see indications of tumbling. Now I agree that there is an imbalance due to copper becoming displaced.  But the effect will be a tumbling bullet. It isn't going to tear apart by RPMs. 124 gr 357 mags run lead bullets at that velocity and twist all day long.