Underwood 200 XTP Brass Blow OUT!

doverpack12 · May 15 2013 11:26:12 AM MDT

I was shooting some new Underwood 200 XTP's through my chronograph this weekend and just seeing how they shot since they just came in the mail. I go to pick up my brass and I have a case blown out. I am trying to attach a picture below. I will also be posting pictures of the box and lot number as soon as I figure out how if this doesn't work. What does every one here think could have caused this its not in the normal location and it seems almost like the brass was a bit long and the bullet wedged it against the barrell and then the slide unlocked and pulled it back causing it to tear with pressure inside but that corner of the brass wedged maybe. Not sure at all it was somewhere in the middle of about 19 shots. Average was 1269 fps has two weird high numbers not sure if I shot way high in the chrono or not. One was somewhere in the 1300+ range and the other was 1400 something. I don't have the numbers in front of me now.

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doverpack12 · May 15 2013 11:27:04 AM MDT

Lot Number followed by box with load information from underwood.

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doverpack12 · May 15 2013 11:27:45 AM MDT

Box

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doverpack12 · May 15 2013 11:29:05 AM MDT

There is a small smile in each piece of brass. Total out of 19 rounds 4 pieces of brass had smiles. The rest just had a pretty good sized bulge.

The_Shadow · May 15 2013 12:08:50 PM MDT

doverpack12, while it is not a good thing to have brass crack or split, it does happen. The treatment process may have left the brass harder/brittle, this can be further aggravated by the loading process. I have seen many Federal 10mm factory brass split upon the initial firing. The Underwood numbers do indicate some higher pressures at those velocities.

That brass may have been damaged in the loading process and turned loose upon firing. If it did not happen to a whole bunch of the casings I'd say the ammo is good to go!

About your higher numbers, try backing away from the Chronograph at least 10' to 15' will help attain better results. And eliminate blast issues.

Be sure to clean the chamber well

RMM · May 15 2013 12:17:56 PM MDT

doverpack, what gun are you firing these out of? How long is the barrel? What is the headstamp on the brass?

I would not fire any more of those rounds in that gun!

Driftwood · May 15 2013 12:18:55 PM MDT

Is this the new ammo that is actually nickel and not brass? I have heard that nickel is more brittle than brass.

Intercooler · May 15 2013 12:50:05 PM MDT

Why does the right side look taller. Top view picture please.

RMM · May 15 2013 01:01:44 PM MDT

It looks to me like the torn material has shifted upwards, but without more pictures it's difficult to say what for sure happened. It does look like brittle brass. This type of case failure isn't too dangerous (not like a web blowout) but if the brass is that brittle it could increase the likelihood of other failures. I want to know if this is Starline brass.

Intercooler · May 15 2013 02:11:10 PM MDT

I will trade or purchase the remainder when/if you decide. ${$default_grin_smiley}$

4949shooter · May 16 2013 04:46:06 AM MDT

Quote from: doverpack12 on May 15 2013 11:26:12 AM MDT
I was shooting some new Underwood 200 XTP's through my chronograph this weekend and just seeing how they shot since they just came in the mail. I go to pick up my brass and I have a case blown out. I am trying to attach a picture below. I will also be posting pictures of the box and lot number as soon as I figure out how if this doesn't work. What does every one here think could have caused this its not in the normal location and it seems almost like the brass was a bit long and the bullet wedged it against the barrell and then the slide unlocked and pulled it back causing it to tear with pressure inside but that corner of the brass wedged maybe. Not sure at all it was somewhere in the middle of about 19 shots. Average was 1269 fps has two weird high numbers not sure if I shot way high in the chrono or not. One was somewhere in the 1300+ range and the other was 1400 something. I don't have the numbers in front of me now.

For a 200 grain bullet? ${$default_shocked_smiley}$

No wonder you had a case blow out.

Intercooler · May 16 2013 06:09:47 AM MDT

I doubt the readings were correct. If you chronograph enough you get grossly false readings every so often. That's why it is better to do long strings and write it down after every shot.

4949shooter · May 16 2013 06:42:31 AM MDT

Yes, I would be interested to see how the rest of the lot chrono's.

sqlbullet · May 16 2013 09:50:43 AM MDT

Hard to tell from the photo...But do those case heads look swollen to anyone else? Dover, do you have calipers you could measure the case head with?

The_Shadow · May 16 2013 10:18:30 AM MDT

They do show some case expansion in the pictures...I tend to thing the case may have be trimmed poorly or damaged prior to or during the loading process. Looking at the section that looked like it was inside the chamber at firing! Machines can cause damage if somethings are out of tolerance... ${$default_huh_smiley}$

BTW DT did have some brass that was less than desirable as people did experience splits...His brass may not be made by Star Line from what I read awhile back. I think he found an overseas supplier if I recall. :'(