Underwood case blowout over on 1911Forums

[4949shooter]

   What was the original Norma. Even that is confusing because I read initially it was a 170gr@1400 FPS then they backed it down to 1300 FPS when it was scaled back. The current 180's are at 1300 FPS which isn't far off.

From my understanding it is 170 @1300 to 1350.

And 200 @1200.

[Intercooler]

I think the powders and firearms of today are better suited to strong 10mm than back then. That's why I give some wiggle room on the loadings.

[REDLINE]

Thanks for posting the pics Bro KV!

It's hilarious to me that Wilson Combat would consider their barrels to have full chamber support.  IMO they aren't even close let alone being seriously hogged out at the chamber mouth.  Overall, I can't see that they offer any better support than a G20.  Don't get me wrong, I'm not saying they don't make a quality gun overall, as I consider them second to none in the 1911 world.  That said, their 10mm chambers offer nowhere near full case support!

And it's not just WC either.  I have yet to see a 10mm barrel outside of a T/C Contender that has full chamber support.  Some, like my Storm Lake barrel are very good, but anything less than 100% IS NOT full support.  Kimber barrels are the closest to full support I've seen, and they aren't full support.

[pacapcop]

That is true,the 180's are not that far off.i I can tell you that is why i personally decieded that regardless of weather it's Underwood or whatever maker of ammo, I  as well as we wanted a suitable ammo that conformed to 10mm specs.Underwood has done a great job brining the 10mm to reality as opposed to factory level stuff on market.Kudos to Intercooler for doing alot of the leg work,no doubt.That being said,there is those looking for a carry round for personel protection and those who hunt.I think the happy medium would be a 170 grain at 1300 and a 200 grain at 1200.That's just my take on it and i think it's acceptable.By the way im carrying Kev's 165 Golden Sabers still,in a G20.Norma settled with a 170 at 1300 after the 1400.

[Intercooler]

Did you catch the area at the feed ramp in the WC that isn't ground back like in my DW? See if you can spot it before I point it out. I thought a 1911 that expensive got the full treatment of hand fitting?

[RMM]

Again, another interesting development.  I do think that Underwood puts out good ammo, but there have obviously been some bumps in the road.  It is interesting to note that the ammo in question here is from an older batch.

There are so many places where stuff can go wrong when mass producing max pressure ammo.  First, 800x meters poorly and is not very forgiving when loaded over max.  Second, when you are trying to mass produce ammo you move quickly (you know, so you can actually turn a profit AND keep prices down!).  When you are moving fast there is more likely to be a round with a little too much powder, too little case tension (bullet setback), or a combination of both.  Every once in a while you get that "perfect storm" with a combination (stacking) of a few variables and you have a blowout.  None of these case blowouts or lost primers have scared me  that much, but the 357 SIG KKM barrel kB looked really bad.

I do think that Underwood makes good ammo, I will continue to use it.  I do know that Kevin has taken responsibility and compensated all those who have had a problem with his ammo. 

[Bro KV]

The owner states that it has the stock recoil spring 22# with 1000 rounds down the pipe I believe.

[sqlbullet]

IMHO....

We can look all around, but it seems to me you don't get 8% more velocity without more pressure.  Either higher peak or flatter curve.  This is where CUP is a better method than piezo/psi.  A flatter curve will crush the copper test cup more where the peak PSI will not reflect that.

We can go on about chamber support or early unlock or out of battery.  But this was two shots in in the same session just a few rounds apart.  That rules out a freak occurance.  Most likely not an out of battery or early unlock.

And while you can argue the case support is not 100%, no autoloader is going to meet the standard of a Thompson/Center.  There has to be a guide path and that means less support on the head.  But, the support should be plenty far back to still be over the actual head.

So, we are left with ammo that is most likely hotter than most 10mm auto is meant to be.  Just because you haven't had an event doesn't mean you wont, or that the load is truly safe in your gun.

I am not ripping on Kevin.  He doesn't hide what his ammo is.  And it is very economical.  I would love to see him load up some "originals" as has been suggested here.  That might cause me to buy a few commercial boxes.

[Bro KV]

The Wilson Rep is saying that early unlock/out of battery cannot cause case failure. Not saying that is what happened in this particular situation but it can happen. Am I wrong here?

[LeMat]

The Wilson Rep is saying that early unlock/out of battery cannot cause case failure. Not saying that is what happened in this particular situation but it can happen. Am I wrong here?

I believe he's saying that a weak/weaker recoil spring does not cause an early unlock/out of battery situation.

[Intercooler]

     If this was MythBusters I guess we would deem this one "Plausible".

Those that would like some originals. Can you share what that is for a 135, 220, etc... and I will pass it on to Kevin? He may not move on it but WTH.

[Intercooler]

Let's see.


   I asked Kevin if he would scale back or do two lines like PBR has done with the Supreme and V-Supreme. Two lines seem like more setup work than just making them all one level.

[4949shooter]

     If this was MythBusters I guess we would deem this one "Plausible".

Those that would like some originals. Can you share what that is for a 135, 220, etc... and I will pass it on to Kevin? He may not move on it but WTH.

I don't believe there were originals for 135 and 220.

[Intercooler]

I don't think so either so what should they all be?

[sqlbullet]

     If this was MythBusters I guess we would deem this one "Plausible".

Those that would like some originals. Can you share what that is for a 135, 220, etc... and I will pass it on to Kevin? He may not move on it but WTH.

I don't believe there were originals for 135 and 220.

In order to determine that your would need to load ammo and have it tested via the CUP method to match the original CUP profile of 10mm Auto.

Expensive to do, so probably not worth it.

The Wilson Rep is saying that early unlock/out of battery cannot cause case failure. Not saying that is what happened in this particular situation but it can happen. Am I wrong here?

I believe he's saying that a weak/weaker recoil spring does not cause an early unlock/out of battery situation.

This is correct.  Certainly early/premature unlock will cause a case to let go.  But in a 1911 that unlock is prevented as long as the bullet is in the barrel. I looked last night but couldn't find the high speed of a 1911 firing, but it shows that the action doesn't move more than about 1/16" of an inch before the bullet leaves the barrel.

It has been further explained by 1911tuner that this is becuase the projectile is still part of the system while in the barrel, and very little recoil impulse occurs before the bullet leaves the barrel.  This coincides with the experiences I have had with squib rounds.  There is noticeable recoil from a "light" round, but none from a squib, even though the differences in pressure may be small.  As long as the bullet is in the barrel, it is dragging the barrel forward with almost as much energy as the pressure pushing on the breech. Since the two are locked, the breach moves backward very little, making unlock impossible.