10mm reloading with Longshot, some Chrony data.

[Turo]

Since recently getting a brand new Glock 20SF, I transitioned my reloading from .40S&W to 10mm, and started experimenting. I loaded the range that Hodgdon suggests, 8.5gr to 9.5gr Longshot with 180gr jacketed bullets, which left a bit to be desired. They gave velocities from 1150 fps for the 8.5gr up to 1213 fps for the 9.5gr. After researching Longshot, 10mm, and the 180gr bullets until I felt like my head was going to explode, I decided to make my first venture out of the lawyer-created safety zone.

Before I go any further, I have to say that reloading outside of the powder manufacturer's published data is dangerous, you can blow yourself up, you might die, and your ex-girlfriend might come back to haunt you from the grave, etc. So please don't take my word for any of this, and don't try this yourself. If you do, don't come crying to me when you're dead.

Using brand new Starline cases, CCI No. 300 primers, Precision Delta 180gr bullets, and a 1.264 OAL, I started my journey. Here's some of my data I collected:

9.7gr Longshot gave me an average of 1247 fps with recoil that felt like a warm .40S&W.

9.8gr Longshot gave an average velocity of 1260 with the smallest deviation out of any of my loads. The extreme spread was only 6 fps, so this load will most likely be one that I'll duplicate for fun range ammo.

9.9gr Longshot gave an average of 1260 as well, but the spread was larger, around 15 fps. The recoil of these still didn't seem super stout, but the sound was incredible. Before, I didn't believe when people called it Loudshot, but now I do.

10.0gr was the highest I went, and the average was a little higher at 1265 fps, but I also had a couple of rounds with velocities as high as 1280 fps.

None of the rounds I shot showed the dreaded "Glock bulge" and none of the primers were flattened nor did any leak.

My goal is still 1300 fps avg out of the stock length barrel, and I'm not sure I'll be able to reach it with Longshot before I see bad pressure signs but I'll try nevertheless.

Anyway, I hope this data helps anybody reloading for 10mm and if it doesn't, oh well. It was fun for me!

[CalTeacher]

Sometimes you can get great results by pushing beyond max published loads, provided that you understand the risks and know how to spot any signs of trouble. Some load data is just oddly conservative...but there's also data where I would never attempt a max charge.

Thanks for the data. I've been looking into a 10mm lately.

[Turo]

Sometimes you can get great results by pushing beyond max published loads, provided that you understand the risks and know how to spot any signs of trouble. Some load data is just oddly conservative...but there's also data where I would never attempt a max charge.

Thanks for the data. I've been looking into a 10mm lately.

You're welcome! I really wasn't too worried about these rounds because the pressure for the 9.5 gr max load was only 34,600 psi when the SAAMI spec is 37,500, almost 3,000 psi higher. Oddly enough, even the hottest loads at 10.0 gr didn't recoil as much as mid range 40 loads using the same powder.

[Bill Steele]

Since recently getting a brand new Glock 20SF, I transitioned my reloading from .40S&W to 10mm, and started experimenting. I loaded the range that Hodgdon suggests, 8.5gr to 9.5gr Longshot with 180gr jacketed bullets, which left a bit to be desired. They gave velocities from 1150 fps for the 8.5gr up to 1213 fps for the 9.5gr. After researching Longshot, 10mm, and the 180gr bullets until I felt like my head was going to explode, I decided to make my first venture out of the lawyer-created safety zone.

Before I go any further, I have to say that reloading outside of the powder manufacturer's published data is dangerous, you can blow yourself up, you might die, and your ex-girlfriend might come back to haunt you from the grave, etc. So please don't take my word for any of this, and don't try this yourself. If you do, don't come crying to me when you're dead.

Using brand new Starline cases, CCI No. 300 primers, Precision Delta 180gr bullets, and a 1.264 OAL, I started my journey. Here's some of my data I collected:

9.7gr Longshot gave me an average of 1247 fps with recoil that felt like a warm .40S&W.

9.8gr Longshot gave an average velocity of 1260 with the smallest deviation out of any of my loads. The extreme spread was only 6 fps, so this load will most likely be one that I'll duplicate for fun range ammo.

9.9gr Longshot gave an average of 1260 as well, but the spread was larger, around 15 fps. The recoil of these still didn't seem super stout, but the sound was incredible. Before, I didn't believe when people called it Loudshot, but now I do.

10.0gr was the highest I went, and the average was a little higher at 1265 fps, but I also had a couple of rounds with velocities as high as 1280 fps.

None of the rounds I shot showed the dreaded "Glock bulge" and none of the primers were flattened nor did any leak.

My goal is still 1300 fps avg out of the stock length barrel, and I'm not sure I'll be able to reach it with Longshot before I see bad pressure signs but I'll try nevertheless.

Anyway, I hope this data helps anybody reloading for 10mm and if it doesn't, oh well. It was fun for me!

Sounds about right. I found it difficult to get above 1300fps out of the stock length barrel with Longshot. I found a 6" barrel got me into the 1300+fps zone pretty easily.

Your 9.8gr load sounds terrific. You are well past the 600ft/lb of ME I consider my litmus test for 10mm using 180gr bullets.

A couple others worth trying in that bullet weight are AA#9 and VV-N105. In my experience #9 will flatten primers very early in the load development process. VV-N105 factory data is way off (in both loads and velocities), so load work ups are kind of mandatory. N105 is incredibly well behaved, very clean, very low muzzle flash, I use it in my SD load.

[Turo]

Sounds about right. I found it difficult to get above 1300fps out of the stock length barrel with Longshot. I found a 6" barrel got me into the 1300+fps zone pretty easily.

Your 9.8gr load sounds terrific. You are well past the 600ft/lb of ME I consider my litmus test for 10mm using 180gr bullets.

A couple others worth trying in that bullet weight are AA#9 and VV-N105. In my experience #9 will flatten primers very early in the load development process. VV-N105 factory data is way off (in both loads and velocities), so load work ups are kind of mandatory. N105 is incredibly well behaved, very clean, very low muzzle flash, I use it in my SD load.

You're right, I loved that 9.8gr load and I'll probably be loading it under some Hornady XTPs to keep as a HD round (and more likely a hunting round if I can ever talk my dad into going pig hunting with me.)

I thought about getting a 6" barrel for a velocity bump, but I'll have to save up for it after I get the 40S&W conversion barrel I have picked out to help get rid of all this 40 brass lying around.

I've heard nothing bad about the Vihtavuori line of powders other than the price, but after reading more about it, I'll have to give the N105 a try. Thanks!

[Bill Steele]

You're right, I loved that 9.8gr load and I'll probably be loading it under some Hornady XTPs to keep as a HD round (and more likely a hunting round if I can ever talk my dad into going pig hunting with me.)

I thought about getting a 6" barrel for a velocity bump, but I'll have to save up for it after I get the 40S&W conversion barrel I have picked out to help get rid of all this 40 brass lying around.

I've heard nothing bad about the Vihtavuori line of powders other than the price, but after reading more about it, I'll have to give the N105 a try. Thanks!

You will love that 40 conversion barrel. I shoot 40's out of it (obviously) but I also load 10mm loads using 40S&W brass, I just load them to 10mm OAL's (you will need to use the heavier bullets like the 180's for something for the brass to hang onto). My barrel came with plenty of freebore to accomodate this type of length. You might ask your barrel supplier if they can accomodate that for you. Makes shooting 10mm target loads a lot less expensive.

Thanks for posting your results, great stuff.

[Turo]

You will love that 40 conversion barrel. I shoot 40's out of it (obviously) but I also load 10mm loads using 40S&W brass, I just load them to 10mm OAL's (you will need to use the heavier bullets like the 180's for something for the brass to hang onto). My barrel came with plenty of freebore to accomodate this type of length. You might ask your barrel supplier if they can accomodate that for you. Makes shooting 10mm target loads a lot less expensive.

Thanks for posting your results, great stuff.

That's the plan!

I have every round I ever made documented with as much data as I could get at the time, so I contemplated putting up the entire spreadsheet but I have a lot of notes that others probably wouldn't need so I figured I'd just post up the important parts.

[DRAB_81]

There are a few guys over on GT's 10mm Reloading Forum have worked up to 10.0gr with 200gr XTP's, so hopefully you don't have any issues with the 180's. Getting the 180's up to 1300fps with a stock barrel isn't impossible, but she ain't easy either. I don't think it's really necessary for a SD load though. My favorite 10mm load is 9.2gr Longshot under a 180gr bullet, and that load has more than enough punch for the nightstand. Try loading 9.2gr with CCI350's @ 1.250" & report back.


.

[Turo]

There are a few guys over on GT's 10mm Reloading Forum have worked up to 10.0gr with 200gr XTP's, so hopefully you don't have any issues with the 180's. Getting the 180's up to 1300fps with a stock barrel isn't impossible, but she ain't easy either. I don't think it's really necessary for a SD load though. My favorite 10mm load is 9.2gr Longshot under a 180gr bullet, and that load has more than enough punch for the nightstand. Try loading 9.2gr with CCI350's @ 1.250" & report back.


.

I'll check my records when I get home today, but IIRC the 9.2 gr loads (well 9.1 and 9.3) didn't even break 1200 fps and felt like a 9mm out of that big heavy gun.

[Bill Steele]

..Getting the 180's up to 1300fps with a stock barrel isn't impossible, but she ain't easy either. I don't think it's really necessary for a SD load though..

This is a really good point. The modern quality JHP's actually seem to work better when not overdriven. Perhaps the one exception to this rule might be the Hornaday XTP's that seem to hold up pretty well to higher velocities.

For sure, when loading Gold Dots something less than 1200 seems optimal. In addition, the reduced recoil of the more managable load levels has to be an advantage.

When building hunting loads with Gas Checked Hardcast, I am thinking the hotter the better.

[DRAB_81]

I'll check my records when I get home today, but IIRC the 9.2 gr loads (well 9.1 and 9.3) didn't even break 1200 fps and felt like a 9mm out of that big heavy gun.

9.2gr seems to be the sweet spot for ES/SD's, and a 180gr JHP @ 1200fps is a damn good load for SD. Being that it feels like 9mm, would make it an even better load to me. Think of it this way, you're getting 200fps faster than most LE .40S&W 180gr ammo, with the recoil of a 9mm. Tons of power, and not too much muzzle rise/flip, so follow up shots will be faster and easier. I'm all for shooting 10mm at its full potential, but it's just not necessary for SD. Most .400 JHP's were designed to expand at .40S&W velocities. When driven too fast, sometimes the JHP "petals" fold back under the base of the bullet, essentially turning it into a FMJ. Like Bill said, the XTP seems to hold up to higher velocities than bullets like the Gold Dot, but again, nuclear velocity isn't necessary. My choice for 10mm SD ammo is the 175gr Winchester STHP (1150-1180fps), but Underwood's 180gr Gold Dot/1200fps load has my attention.

[MIAMIbaseballer]

Since recently getting a brand new Glock 20SF, I transitioned my reloading from .40S&W to 10mm, and started experimenting. I loaded the range that Hodgdon suggests, 8.5gr to 9.5gr Longshot with 180gr jacketed bullets, which left a bit to be desired. They gave velocities from 1150 fps for the 8.5gr up to 1213 fps for the 9.5gr. After researching Longshot, 10mm, and the 180gr bullets until I felt like my head was going to explode, I decided to make my first venture out of the lawyer-created safety zone.

Before I go any further, I have to say that reloading outside of the powder manufacturer's published data is dangerous, you can blow yourself up, you might die, and your ex-girlfriend might come back to haunt you from the grave, etc. So please don't take my word for any of this, and don't try this yourself. If you do, don't come crying to me when you're dead.

Using brand new Starline cases, CCI No. 300 primers, Precision Delta 180gr bullets, and a 1.264 OAL, I started my journey. Here's some of my data I collected:

9.7gr Longshot gave me an average of 1247 fps with recoil that felt like a warm .40S&W.

9.8gr Longshot gave an average velocity of 1260 with the smallest deviation out of any of my loads. The extreme spread was only 6 fps, so this load will most likely be one that I'll duplicate for fun range ammo.

9.9gr Longshot gave an average of 1260 as well, but the spread was larger, around 15 fps. The recoil of these still didn't seem super stout, but the sound was incredible. Before, I didn't believe when people called it Loudshot, but now I do.

10.0gr was the highest I went, and the average was a little higher at 1265 fps, but I also had a couple of rounds with velocities as high as 1280 fps.

None of the rounds I shot showed the dreaded "Glock bulge" and none of the primers were flattened nor did any leak.

My goal is still 1300 fps avg out of the stock length barrel, and I'm not sure I'll be able to reach it with Longshot before I see bad pressure signs but I'll try nevertheless.

Anyway, I hope this data helps anybody reloading for 10mm and if it doesn't, oh well. It was fun for me!

Thank you very much for posting this. I'm about to start reloading 10mm in 3 weeks when I get back to Cali and I'm using exactly what you used except Win primers. Did you notice any difference in accuracy with these loads?

[Turo]

Thank you very much for posting this. I'm about to start reloading 10mm in 3 weeks when I get back to Cali and I'm using exactly what you used except Win primers. Did you notice any difference in accuracy with these loads?

I haven't shot any of these for accuracy, just velocities, but I'm not accurate enough to notice differences in the precision of handgun rounds. I'll probably bench this gun at some point, but until then I'm just plinking around.

[Turo]

I'll check my records when I get home today, but IIRC the 9.2 gr loads (well 9.1 and 9.3) didn't even break 1200 fps and felt like a 9mm out of that big heavy gun.

Just got home and double checked, I was right on. My 9.1gr load averaged 1188, and the 9.3gr load averaged 1205. I guess if I was loading 180gr Gold Dots or something similar for HD I would drop the load down to around there, but I want to load lighter weight bullets for HD. As soon as I can get some 155 or 165gr fmj bullets to practice with I'll build up a HD load around the same weight.

BTW, does anybody have any info on the expansion velocity for Hornady's 155gr XTP bullet? I've got some lying around and I might load some up for fun.

[DRAB_81]

Check out this thread on GT:

http://glocktalk.com/forums/showthread.php?t=1340792

It's a LOOOOOOOONG read, but it's the most comprehensive 10mm expansion testing I've seen. It's not true ballistics gelatin, but it's better than most water jug or wet pack tests. The guy that did the testing, 21Carrier, used a bunch of different JHP's @ true 10mm velocities.