I have 3 guns in 10mm.  EAA and S&W handle the 200 gr fine but get case separation in my 6" Perfect 10 STI.  One separation was so bad the gun went back to STI.  The G20 handled the 200 gr Underwood ok with stock barrel I just couldn't hit the side of a barn shooting from the inside.  Not the only Glock I couldn't shoot.  Been shooting a 1911 for 62 years.

Your rack (bed) on the SSBN609 was 25" wide and 6' long.  The first 30 days home you mustered every 3rd day.  First 30 days back at the boat you worked your behind off fixing things.  I worked in the engine room area.  When you went to sea the lowest rated guys got to stand port and starboard watches (12 hours) till the new guys were able to stand watch. Your day became only 18 hours.  100 plus days not seeing the sun!  Everyone wore a one piece jump suit.  If you were in the nuke part of the Navy you were tested every watch to see how emergencies were handled. We had movies every night, ice-cream just about 24/7, stake and lob at once per patrol.  We did fall 300' before the "Chicken Switches" were pulled.  Seen guys that hadn't seen the whole patrol as our watches, sleep times, and off times were different.  Only red lights were on in the sleeping area unless it was cleaning time.  Had one ol'man that only held two field days one when we went to sea and one when we came back.  Only place in the military it was legal to gamble.  Boat took a percentage of all pots then put on one big party for the men and their ladies and one where the kids were welcome.

The only maker for CCW I'll buy from is Karmer  http://kramerleather.com/  I use his Inside The Waistband #2 Gun Holster - Horsehide Inside The Waistband #2 Gun Holster - Horsehide  I carry 1911's, S&W 640, Glock 17, S&W1006, and a EEA 10mm.  after investing an untold amount of money in holsters I find Karmer works for me.

Will pick up some Kroil spray tomorrow and try the over sized brush after soaking for an hour or 2.  Not good at posting pictures but will try.  I don't have the primer/head section, it was left at the in-laws where I was shooting and sister-in-law pitched it.

Shooting Underwood 10mm AUTO 200 XTP J.H.P. in my STI PERFECT 10 and had a case seperate on me. How do I get the front 1/3 of the case out of the chamber? Don't have a broken case extractor and can't find one for 10mm/.40 S&W.

STI Perfect 10 condition 1 in a Kramir IWB horse hide, Colt 1903 slide lock off one in chamber in a horse hide pocket holster. 

Sold my Glock, just can't love that gun.  Still have Smith, EAA and my love STI Perfect 10.  The 6" barrel makes it the perfect shooting gun.  The 6" barrel and 200 gr Underwood Ammo drop anything deer size and smaller that I have shoot.  It now holds 20+1 which is more than my Glock held. 

If you could only have one factory loaded round what weight would you want?  I like a 200gr lead flat nose to hunt with and could make do with that one weight.  I would like 1100-1300 fps loadings which would work on anything animal or man in Indiana.  Isn't it great we don't have just one or two loadings to pick from?

I have a Perfect 10 and want to install stronger springs but am having problems finding 6" springs for a STI and non for the  10mm.  Anyone have a source for the springs.  Wolff was no help!

I just bought a Glock, S&W 1006, EAA Witness and own a STI 6" and wonder if anyone has this setup and what one brand ammo works good in all 4 for putting holes in paper.  Underwood 200gr was used with the EAA and S&W.  Glock is new.  Doubletap is used with the STI as Underwood 200gr would flatten or back out the primer.  I would like all to give 2-2 1/2" from a ramson rest.  The STI has done less than 1"  several times with some hand loads.  I can't shoot that good any more though, old eyes.

read http://10mm-firearms.com/reloading-10mm-ammo/underwood-ammo-in-a-sti-perfect-10/

You will hate it so sell it right now before you get in your hands   I have one and use it for EDC.  It has dropped 3 coyote out and  around the barn.  I carry Buffalo Bore in it after having flat primers and gone primers from Underwood 10mm Auto 200 Grain XTP Jacketed Hollow Point.  Hit one coyote, with  the Underwood, between the shoulder blades and came out his chest.  It was bad news for him.  Most times coyote stay on the outside of my fences.  I was a Colt .45 ACP guy for years but within the last year I have bought a single shoot EAA Witness (should be 14 round simi-auto), the STI, and a S&W 1006.

Will there will be no more Underwood in the STI as the gun has became my favort around the farm.  I'm loaded with Buffalo Bore Heavy 10mm Ammo - 220 gr. Hard Cast - FN (1,200 fps/ME 703 ft. lbs.).  Cases look good, primers all look good and it feeds good.  3 rounds and aim and impact are to same point at 25 yards.  Hope the Buffalo Bore are better than the Underwood for my STI.

The barrel is listed as a ramped barrel with a fully supported chamber.  I have put 5 rounds of Underwood 10mm Auto 200 Grain XTP Jacketed Hollow Point.  The case looked like the EAA had shot it.  2 had the primers gone and the other 3 had flattened primers.  The gun didn't load the next round, the nose was stopped about halfway up the ramp.  Dropping the mag and pushing on the rear of slide the round finished loading.  Don't think I'll use the 200 grain XTP in my STI as I don't like the primers gone or flattened.

I have a Perfect 10, just picked it up first of the month.  I also have a 10mm Witness that is mostly a single shot. 
I used Underwood in the EAA 200gr down to 155gr.  Can I shoot the Underwood in my STI?  My LGS owner likes the 10mm so he keeps several different brands on the shelf, just not as hard hitting as the Underwood, when he can get them.  I have used the 200 gr Underwood on coyotes and like how they drop.  Don't want to hurt the STI but do want to shoot the most power I can.  I want to use it for hogs.  Everyone I know shoot the Glock or EAA with 2 guys shooting a S&W 1006.  No one is shooting any 1911.