10mm heavy bullet load data?

[Alibiiv]

I just purchased some 220gr hard-cast bullets from Rim Rock bullet company. Now that I have the bullets I cannot seem to find a load for a bullet heavier than 200gr for the 10mm.. I recently picked up a Hornady #10 reloading manual, the manual lists a maximum load of 7.3gr of Longshot for a 200gr bullet. I was told that Buffalo Bore uses "7.1gr" of Longshot in their 10mm ammunition. I guess I could do some pressure testing with different loads in .05gr increments, don't like doing that with a handgun, or any gun. With a rifle there are familiar signs when pressure is getting too high, with a handgun that is not such a luxury. I've checked some of the other forums, this situation does not seem to be unique to these bullets. What I did find was that for any accuracy out of the heavy bullets in a Glock the bullets have to be moving at least 950fps to stabilize. Any one have suggestions or resources for load data for the heavy, 220gr, hard-cast bullets?

 

[Frog4aday]

Hey Alibiiv,
I've been searching for you and can't find any 220 grain cast load data for the 10mm either. But I did come across this tidbit of wisdom from the guy that produces the 220 grain Buffalo Bore ammo. He refers to needing a stiffer recoil spring than 'stock' in the Glock 20. Here is the partial quote:
Owner of Buffalo Bore Tim Sundles on Heavy 10mm Ammunition:
Full power 10mm ammo has always generated enough recoil and pressure to require a pretty stiff recoil spring in your handgun - this of course depends on several variables such as your slide weight, etc. When the cartridge fires, it generates enough pressure/recoil to prematurely open your breech face in some guns. When this happens, the opening breech face has an effect on the burn rate of the powder. This can result in some fairly high extreme spreads in velocity. If you are experiencing extreme velocity spreads of more than 50 fps, simply install a stiffer recoil spring. For example, I have an original Colt Delta Elite. This gun with the factory spring runs extreme spreads of about 35fps with both of these 10mm loads. I am happy with 35 fps, so I leave the Delta Elite as is. I also have a custom built Para Ordinance with a Nowlin barrel. It runs extreme spreads of about 70 fps with its original recoil spring. When I install a spring that is 4 lbs stiffer, the extreme spread drops to about 35 fps. The new Glock model 20 comes with a recoil spring that allows the breech face to open too soon and my new Glock model 20 will get extreme spreads of about 100fps with the factory spring installed. When I go to a stiffer recoil spring, the extreme spreads drop to about 50 fps in my new Glock model 20."

Full write up can be found here: https://www.midwayusa.com/product/1001484052
(scroll down to wear it shows PRODUCT OVERVIEW)

 

[sedancowboy]

I hear that there is some data over on http://www.10mm-firearms.com/
If I were to try and develop a load for the 220 hardcast I would try AA#9

 

[yorke-1]

I'd start 10% a below the starting charge for a 200gr jacketed bullet. Cast bullets build pressure differently than jacketed bullets, so you should be well withing safe working pressures even with the heavier bullet. From there I'd work up slowly until the gun told me I was at max based on recoil, shell ejection and case head condition.

Working up loads in semi autos is always a bit tricky.

 

[Frog4aday]

This website shows three loads for the 220 grain cast bullets but if you aren't a paying member (which I am not) you can't see the powder data.
https://ammoguide.com
It's $22 a year to join.

I did find data for a 205 grain cast bullet in MODERN RELOADING (2nd Edition). Maybe it gives you a place to begin?
ACCURATE #9 - START LOAD = 10.6 grains (1018 FPS); 1.250" OAL

 

[Mackinaw BOB]

I was doing some research on loading for the 10mm, but only for 180gr. Everything I read said blue dot was the go to powder for 10mm. Sorry I couldn't be more helpful

 

[Gar Guru]

I would call and talk to one of the technicians at Alliant Powder and/or IMR Powder for suggestions. I use Unique in 10mm and like it for 180 gr bullets. I have a lyman hard cast only manual at home I will check for you also. The thing I dont get about everybody saying use lighter powder charges for cast bullets vs. jacketed bullets is this... I recover almost all of my bullets in a bullet trap to recycle and none of the bases are deformed and none of the powder coating is missing from the base of the bullet. Appears to me my cast bullets can withstand as much or more pressure than a copper jacketed bullet. Can someone enlighten me on this?

 

[rsbhunter]

!!!!!!NOTE!!!!!! POST HAS BEEN EDITED, SHOULD BE 200gr HARDCAST !!!!!!!!!As far as heavy, above factory, loading for glock 20's,it is a lot of ?????? Depending on generation, recoil spring, stock bbl(on some gens) and load data, it can honestly become an accident looking for a place to happen. Please research all you can, go to 10mm .com (I believe). They have bunches of info....just filter through th b.s.. watch out for "nuclear loads".....they are called that for a reason. Anyway, I shoot a 2nd gen glock 20 with a 6" Storm Lake bbl, a 24lb recoil spring and use 800X and Long Shot powders a lot. Recoil gets to the level that my trigger finger gets sore from slapping the trigger guard. So, PLEASE be careful,kabooms are real events...pm me if you wish, I shoot (WRONG WEIGHT220gr) 200gr hardcast loads...Will share my load info, it is not an insane load....rsbhunter

 

[Iron Worker]

Hey Alibiiv,
I've been searching for you and can't find any 220 grain cast load data for the 10mm either. But I did come across this tidbit of wisdom from the guy that produces the 220 grain Buffalo Bore ammo. He refers to needing a stiffer recoil spring than 'stock' in the Glock 20. Here is the partial quote:
Owner of Buffalo Bore Tim Sundles on Heavy 10mm Ammunition:
Full power 10mm ammo has always generated enough recoil and pressure to require a pretty stiff recoil spring in your handgun - this of course depends on several variables such as your slide weight, etc. When the cartridge fires, it generates enough pressure/recoil to prematurely open your breech face in some guns. When this happens, the opening breech face has an effect on the burn rate of the powder. This can result in some fairly high extreme spreads in velocity. If you are experiencing extreme velocity spreads of more than 50 fps, simply install a stiffer recoil spring. For example, I have an original Colt Delta Elite. This gun with the factory spring runs extreme spreads of about 35fps with both of these 10mm loads. I am happy with 35 fps, so I leave the Delta Elite as is. I also have a custom built Para Ordinance with a Nowlin barrel. It runs extreme spreads of about 70 fps with its original recoil spring. When I install a spring that is 4 lbs stiffer, the extreme spread drops to about 35 fps. The new Glock model 20 comes with a recoil spring that allows the breech face to open too soon and my new Glock model 20 will get extreme spreads of about 100fps with the factory spring installed. When I go to a stiffer recoil spring, the extreme spreads drop to about 50 fps in my new Glock model 20."

Full write up can be found here: https://www.midwayusa.com/product/1001484052
(scroll down to wear it shows PRODUCT OVERVIEW)

I have a Glock MOD 40 What weight and where can I get the right spring ?

 

[Frog4aday]

Hey Iron Worker, I'm not seeing recoil springs for the Glock 40 widely available, so not sure where to point you. But for the Glock 20 shooting heavy loads up to 200 grain bullet weight, I am using a 20lb recoil spring. If I was going to try 220 grain loads, I would probably look at getting a 22lb recoil spring.

The "issue" is this - a stiffer recoil spring helps keep the barrel locked up a fraction longer on those heavy loads (which is good!) but it also closes the slide sooner, too. If the magazine spring isn't stiff enough to shove the next round up to be chambered fast enough, you get failures to feed. Trying to strike that balance where everything still works is the 'trick'. And you only know by testing in YOUR gun, with your 'hold' on it (grip hard? grip soft? stiff wrists? flexy wrists?) So many variables.

What I do know is your frame will take a beating if you try to run those 'hot' 200gr and 220gr bullets through a Glock 10mm with 'factory' weight springs. For a guy running a mag of them through to test reliability, then carrying them for bear protection, probably not a huge issue (not enough rounds through the gun to be truly harmful.) But for someone doing 'load development' and 'practicing' with those heavier rounds, the gun will take a beating without some consideration toward increasing recoil spring weight.

 

[rsbhunter]

Frog4aday, research showed NDZ has spring, guide rod adapter(?) And guide rod for the 40. I don't know about the 40, mine is an old model. But that should get you going...might want to get a couple different springs, from what I've learned,a super heavy spring, though it slows slide rearward movement, increases forward speed...? rsbhunter

 

[Alibiiv]

Wow thanks to everyone for their interest and replies to this thread. It appears that there are a number of unknown variables to this topic. I have read that you need to replace your recoil spring to a heavier spring like 22 to 24lbs. Then research showed that if the recoil spring is changed to a heavier spring then the gun is locked in to shooting heavies, otherwise the lighter bullets will fail to eject. I called Buffalo Bore and spoke to, I believe, the owner of the company. He stated that the 220gr, 10mm Buffalo Bore ammunition was designed and manufactured for the Glock 20. I was more concerned about the hardness of the bullet and leading of the rifling. At this point, for me, it is looking like maybe the 220gr hard cast bullets might to be a bullet for the 10mm., but.....I've got 300 bullets in the basement that I'll have a chance to play with to find out. I appreciate all replies and information that everyone has offered or has to offer. I'm going to keep digging...........

For those looking for heavier recoil springs, "WOLFF" springs, 22lb recoil spring for Glock 20, $29.95. I used these folks for just about any spring for my firearms, the company's product line is quality as is their shipping.

https://www.gunsprings.com/GLOCK ®/cID1/mID5/dID116#123

Update on the heavy recoil springs from Wolff. I found that they have the heavy recoil springs for Glock 20's Gen1-3, but....the recoil springs for Gen4 Glock 20 has to have an adapter due to the guide rod hole being larger on the G20 Gen4. Can get the adapter from from ZEN Technologies, haven't researched that as of yet.

 

[rsbhunter]

Alibiiv, yes, it is mind boggling once you get into the experimental. There is so much variable in bbl's, springs, chamber's, etc. I edited my post because I mistakenly stated 220gr, when it was 200gr bullets I have loaded. Should have looked at what I loaded before I replied.....Anyway, good luck, be careful....rsbhunter

 

[yorke-1]

The thing I dont get about everybody saying use lighter powder charges for cast bullets vs. jacketed bullets is this... I recover almost all of my bullets in a bullet trap to recycle and none of the bases are deformed and none of the powder coating is missing from the base of the bullet. Appears to me my cast bullets can withstand as much or more pressure than a copper jacketed bullet. Can someone enlighten me on this?

I typically use a higher powder charge and get higher velocities with a cast bullet compared to a jacketed bullet of the same weight. In the 44 Mag I shot a 330gr hard cast bullet at the same velocity as a 300g jacketed bullet, and used almost 2.0gr more H110. I had the same results with all the other magnum revolvers as well. Using the right alloy or a gas check will prevent damage to the base of the bullet and help with some of the fouling and accuracy problems too.

I never had any issues shooting cast bullets in a factory Glock barrel as long as I used the proper bullet alloy. Shoot soft lead in just about any gun with velocities over 1000 fps and you're going to have a mess to clean out of the barrel, unless you use gas checked bullets.