Thank you for that information. THe only hodgdon book I have is pretty old,. and my newer lymans and speer are silent on the sr4756. I think my hornady is  #3,.and there are some things that were not "a thing' yet when they wrote it.  I'll probably see how 4756 meters and use it up. Apparently it does sit alongside 800x in some of those handload charts.   

800x is cool, but even when I trickle my loads perfectly, I get a fairly large velocity spread (I think at least 30 feet per second..don't have my data in front of me).

I noticed that SR4756 was right next to 800X on the burn rate charts.  I have some of that I have never opened, is there is a reason there is not any 10mm loads listed for it?  I would love to go away from 800x since #1 it meters poorly, and #2, even if I trickle to perfection,..the velocities vary quite a bit.    I was going to switch back to Power Pistol, but then I saw that SR4756 was right next to 800x ,. So I thought I would make a post here and see if anybody knows any info on it.  thank you in advance.

With 800x, trickled in my hornady auto charge,.. in my 44 mags. my s.d. is incredibly low...like 5 or less fps.
It is not as low in my 10mm, that's for sure.  I just did (yesterday) about 3 mags. full,..trickled by my hornady auto charge. Still a  s.d. of 20 or 30 fps. give or take, velocity was  avg. 1270ish 177.5 gr. hardcast. I don't yet know the answer to that (why the s.d. is near zero in a 44 mag and not the same in the 10mm) unless my auto charger was acting up.  It could also be that a semi-auto just doesn't get as low of a  s.d. due to how they operate.

When you make a statement that  IMR left the max load at 30,000 psi,..because the pressure was erratic,..I look and cannot find that statement made by IMR  at the time they did the load development....anywhere...anywhere on this planet...And I've been looking for a long time.  The pressure will be erratic with erratic charges,..that's a given. But erratic under a certain charge? ...The same charge they list at 30,000? Should it have said 30,000 +/- 10kpsi? Maybe it should have. I don't know on that one.

The chamber wall thickness of my kimber 10mm 1911 is quite a bit thicker than a 44 mag. and for that matter,..is thicker than the 454's that I have data on. I've owned two 454's, and both had cylinder  (outside) walls around .110",.. The kimber is closer to .125 or more (didn't use the Mititoyo on the Kimber,..so the blade width of the crap one from Cabelas will overstate the thickness quite a bit more than the thinner Mititoyo will).

I have personal friends who have had kabooms. EVERY......SINGLE.......ONE.......of them was using a fast powder and either had a detonation or a double charge. I am 60 and still waiting for someone I know to have a kaboom under a too heavy dose of a slower powder...one that fills the case. (I believe that in these types of court cases...for a defense,  the ammo. mfgr. states the powder they use,..and then says something like: you can't get enough of this powder in the case (even if you want to) blow the gun up,..and then they proceed to wait A LOOOOONNNNGGG TIMEEEE for the prosecuting attorneys to try and prove them wrong. This kind of thing usually just wears a gun out faster than lighter charges would. An acquaintance of mine  recently did a double charge of bullseye in his 45 glock (he was new to reloading, and quite young)..and it blew the magazine out the bottom of the gun,..and scared the crap out of him,. but the gun was ok, all he needed was a new pair of shorts.

With the short time I've used 800-x (under 500 loads),..I can tell you that is does a pretty good case fill. I have not tried to compress it,..and I don't know if it "likes' compression like H110 does, etc., But I would like to know how much 800x the case would hold,..and still let you seat your bullet properly. 

I suspect that after IMR and Hodgon became the same company,..the old 10mm imr data was left "as is" originally and then no longer used.  I am guessing that there is a good chance that the original folks involved with the 180 gr. 800x testing are no longer with us. At some point Hodgdon decided they would use their own data and the IMR data disappeared.  The original 357 mag was about 1550 fps. And the load is well known,..about 15.3 to 15.5 grains of 2400. under a 158 grain bullet. Explain to me how a "normal" load, becomes almost non existent after a few decades?  Did all the original 357's blow up because they didn't like the original load? (I load this exact load for all my 357's..and the velocity is exactly what it was back then in an 8" Registered Magnum.) 

The last paragraph leads to the following question: Where are all the blown up 10mm guns that caused the original data to be "pulled" from officialdom? I'll wait.................................              ..................still waiting.   I hear some of the original 10mm 1911's back then weren't as strong as the  ones now.................so I'll even wait a little longer while someone finds the information.

When I have some extra money and connections,..I fully intend to send some rounds to someone with a pressure barrel so I can answer this once and for all. With all the internet yapping you would think that someone out there would send rounds and have them tested. They do that  for revolvers quite often.

I've used power pistol a lot, 800-x some,..and haven't yet used longshot on the 10. I am going to be loading some with that soon,..I've got a couple pound of it around here somewhere. 
    By the way,..I thought Ka-boom refers to blowing your gun up,..Not wrecking the slide, etc.,  Many people who have done double charges in 1911-style pistols (or glocks, for that matter) have had the wonderful experience of the slide slamming back (sometimes wrecking things,..sometimes not,...._) .........and the magazine getting blown out the bottom of the gun...................and a short time later a tiny trip home to get a new pair of shorts.

The thing about 800x is that it gets you power without  having to go to high pressure. I think the 10mm is rated at 37,5kpsi max or something like that (although I hear that the original bren ten developement folks went wayyyy higher than that.),..And a regular high velocity load of 800x is around 30kpsi.  So,, my question is,...can you even get enough 800x in the gun to do a kaboom?  Wish I had the cash to send loads off to test labs with pressure barrels,. That would really be nice.

 I do have that Hornady Electronic powder thrower.  I will be using it when I get enough empty cases to do another loading session. Probably 9.3 gr.  I am so curious to see if the standard deviation goes down to a few feet per second when I use the Hornady to dial them in. That Hornady DOES try my patience.

I'm shooting hardcast. It's a lee truncated cone 175 grain bullet mold,. I believe the alloy I am using comes in at around 177 or 178 grains, but don't quote me,..my notes aren't in front of me right now. I use gas check molds for bullets in my magnum revolvers,..but the 10mm isn't really hot enough to require gas checks. I've shot a handful of jacketed in the past, as well as some factory,..but, for the most part,. I stick with the hardcast that I do myself.

I've recently decided to start using 800x. (Kimber FS 1911), What a  pain in the rear it is for a powder thrower to be consistent.   Anytway,. Took my chrony out to check things out,..and at 9.3 gr. 800x (I don't believe it is in current load books),. I am getting 1275 fps with quite a LARGE standard deviation,. I assume this is completely due to inconsistent powder charges (I didn't trickle these in at all,..just checked them and had my powder cop set so they wouldn't get too out of spec).  So I had some empty 44 mag cases,..and two or three weights of bullets I wanted to try 800x in,. And so I used my Hornady auto charge (not sure the exact name I am supposed to call it) and let it trickle each charge to exactness.  All I can say is HOLY CRAP,.. When trickled to perfection, I was getting readings where all velocities were within 5 fps of each other.    Of those of you who use 800X,..AND TRICKLE your loads down to the exact amount,....are you getting standard deviations as small as I was in my 44 mag.
     I will be trickling my  next loads (don't know when that will be),. and will be hoping they are all nearly exactly the same muzzle velocity.    I have a hunch I.M.R. stopped at 30,000 psi because they knew full well there is not a powder thrower on the market that can make 800x charges very accurately and percentage will have a healthy overcharge.
    OK, Let me know how your trickled handloads with 800x do as far as standard deviation is concerned.

Don't know of many real world situations where you have time for more than a shot or two. (brown bear).  I did read an article once written by a bear hunting guide...he stated that 240 gr. hollow points were the best BECAUSE,...the 240hp would more often than not change the bears focal point from YOU to the place they just got shot... and that would definitely give you more time. I guess they are nasty enough on the receiving end to get your attention.

When I said you may not get a second shot...I was referring to how fast bears are. I don't have a personal experience,...but have read over and over that you REALLY need something that you won't need a second shot on.

I think when the ruger alaskan first came out..there was an account where a man used it in alaska and the bear he shot fell past him as it went down....GOOD THING IT WAS GOING DOWN!

Quote from: Popapi on January 29 2017 11:45:06 AM MST
Guys I'll be up in Alaska hunting moose and caribou in late August and early September. Need some advice on some hard cast lead bullets that won't lead the barrel up on my G20 with BarSto. Looking for something that would be good on game such as brown bear for protection. Was looking at DTs Wide Flat Nose Gas Checks and also Underwoods factory loads also.

First of all, use the bullet that will do the job the best....and just remember to keep your gun clean.

Second... (I'm sure you've heard this a million times)...you really should come up with a bigger gun if you are going to tangle with a brownie. Even if you could borrow a 454 or 500 or 44 mag w/buffalo bores...you would be better off. They say many times you never get a second shot.