On the hotter stuff I see .428 - .431when measuring the expanded brass. Your results seem really low and makes me wonder if that is forcing everything out the back. I think their must be a nice balancing point.

What could be happening is with the chamber tight, the brass is expanding rearward as the pressure exceeds the brass strength.  I never really liked going above 200gr as the case capacity is diminishing for the bulky powders.  In this instance it looks like they are using a faster powder.  This is another reason why handloading your own allows you to develop loads with powders that are suited to the entire setup.

Quote from: The_Shadow on March 23 2015 07:50:57 AM MDT
What could be happening is with the chamber tight, the brass is expanding rearward as the pressure exceeds the brass strength.  I never really liked going above 200gr as the case capacity is diminishing for the bulky powders.  In this instance it looks like they are using a faster powder.  This is another reason why handloading your own allows you to develop loads with powders that are suited to the entire setup.

I agree with this 100%.

 I agree with this too.  I have absolutely no problems with any of my reloaded 10mm.  I have found what works well with my gun that gives me decent accuracy, the velocities that I wish to achieve, and no unusual signs of pressure. 

The only reason I even purchased a few boxes of Remington UMC, Underwood and Buffalo Bore ammo was to give me something to fire while trying to track down all the necessary components and equipment to reload my own when I first purchased the gun. 

I prefer the 180 grain projectiles the best and that's all that I have reloaded to date. The other factory stuff was just what I could find in local stores or on the net at the time of purchase.  That being said, the 180 grain Gold Dots from Underwood have functioned just fine in my gun.  But my personal preference is to load pulled 180 gr Federal HST's for social work or 180 gr. Hornady XTP's for woods carry or practice.

I don't even mind the factory Remington 180gr UMC stuff.  It's easy on the cases which is nice for reloading. And it's something mellow enough that my Wife will shoot it. Just wish it wasn't so dog gone expensive.

Hey Shadow,

I just went and tracked down your Buffalo Bore 220 hardcast  pull down thread to compare to mine. It's hard to tell from the pictures because I'm looking at it on my phone, but the powder looks to be the same. Also the charge weight is the same at 8.4 grains.  What I did notice that was different is that you listed a Nickel colored primer being used, while mine has a plain brass colored primer.  Possibly a difference between CCI and Winchester maybe? I know from my own testing that when switching an otherwise identical load from the CCI 300 to the Winchester LPP that the Winchester produces a lot more velocity and presumably higher pressures.  Maybe this has something to do with my scenario.


This thread here shows my chrono differences between otherwise identical loads when switching between primers - http://10mm-firearms.com/reloading-10mm-ammo/federal-180-grain-hst-handloads-chronograph-results/

I had the same issue with Buffalo Bore 220's popping primers in Glock 20. I posted a thread about it last year.

I ended up handloading my own soon afterward and ended up dropping the charge to 6.4 grains of BE-86 (same powder as BB, same bullet, same brass, but with WLP primer) to get reliable feeding. The BB was popping primers and constant failures to feed with 22# Wolff spring and KKM barrel. Now I run stock spring and KKM.

I would advise to stay away from the ammo, it's clearly overpressure. My handloads for the 220 chrono low, but I have Beartooths on order.  Plan to push those to almost 1200fps. I would also like to say that since handloading, and staying away from DoubleTap, Underwood, and Buffalo Bore my feed issues entirely disappeared with the gun returned to stock spring and KKM barrel even with some nasty hot Power Pistol loads.

   I don't think it's overpressure. Maybe something can be done to open up the barrel a little?

Dieselman,Yes it could very well be the BE-86 powder they were using.  It was difficult to see in your picture.  It is similar looking to Power Pistol but has whitish flakes in the mix.  I have been trying to find BE-86 locally, but have not found any to work with.

radiotom, you had the same experience as Dieselman so it has to be the power is just too fast and that heavy bullet takes a gentler shove to get it moving.

radiotom,  I was looking at your older thread about popping primers yesterday before I actually posted my own thread.  It seems clear that we both had the same issues with two completely different guns.  I agree that my best course of action is going to be to just develop my own hard cast load. Probably in the 200 gr variety.

Hey Intercooler and Shadow,  what do you think about my different primer theory? Think that could have any merit? 

Also to radiotom, do you remember if your bb load that was blowing primers had a nickel colored or brass colored primer in them?

Yes the change in primer could make a difference.  I will also say that CCI primers do fit tighter than the Winchester.  I have had CCI crush trying to get them in some brands of brass.  A different primer may drop the pressure slightly and BE-86 shouldn't need a magnum primer.  But to me it is a combination of things that include the primer, and fast burning powder under a very heavy bullet.

The primer and powder pressurize up so fast the bullet doesn't have a chance to start down the bore before peak pressure hammers the case head of the brass and primer.  Kind of like the pop of low octane gasoline and the long steady push of burning diesel fuel.

The primers in mine were brass colored.

Quote from: radiotom on March 23 2015 05:14:17 PM MDT
The primers in mine were brass colored.

Thanks radiotom. It just leads me to believe that maybe a load was worked up by buffalo bore that may have seemed ok with the components used at the time and then due to the shortages everyone is experiencing maybe a substitution of primers was made without bothering to reduce the charge rate and safely working back up. 

Regardless, I agree with what has been said here by all of you.  It's too much pressure for my gun. Whether that's caused by one thing or a combination of things. I like hot 10mm as much as the next guy, but want to still have a little margin of safety for factors that a shooter might run across like temperature fluctuations and the likes. But these are just too hot. 

I too agree with having a margin of safety!  A few feet per second are not worth damage to the firearm or the shooter.

I would like to run run of them empties with the popped primer through my sizing die and see if a lot more effort is needed to size them.

Quote from: The_Shadow on March 22 2015 02:35:18 PM MDT
I have seen some StarLine brass have loose pockets...may or may not be the issue.
Heavy charges with slower burning powders can cause the casing to be expanded tight to the chamber walls when ejection starts, primer may move as the barrel drops from lock up.

I have some nickel plated Starline 10mm brass I got from MidwayUSA, and it has a very tight primer pocket.

I have not checked the brass I got from Earl's group buy.



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