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OVERTHROATING?

Posted: Fri Jul 25, 2008 5:40 pm
by jaeger45
OVERTHROATING?


A friend had his Para 16.40 "fine-tuned"- his words - by a gunsmith. Who, apparently, turned out to be a "gonesmith."

These are the results:

Image
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Overthroating?

Any remedy, or is it too far gone?

Posted: Fri Jul 25, 2008 6:03 pm
by recumbent
I'm no expert but I'd say too far gone.

It's easy to remove metal but hard to put it back, especially in the chamber.

Posted: Sat Jul 26, 2008 3:30 pm
by Bullseye
Time for a new barrel. Plus I'd be taking that barrel and bulged case back to the hacker and have him pony up for the new one.

R,
Bullseye

Posted: Sun Jul 27, 2008 10:09 am
by greener
I don't think I'd be shooting that pistol until I had a new barrel.

Posted: Sun Jul 27, 2008 12:30 pm
by Georgezilla
Looks like he fine tuned it to be ruined. This is one reason why I'm wary of going to any gunsmith without a good pedigree. Thankfully I still haven't needed a smith, so I have time to look.

Posted: Sun Jul 27, 2008 2:25 pm
by greener
Looks like a hotter load or a weaker casing could result in some real excitement in the chamber. For those of us who don't have a clue about this, anyone know what he thought he was doing?

Posted: Sun Jul 27, 2008 4:56 pm
by bearandoldman
Maybe it was not really broke in the first place so it did not really need fixing. Some guys like to have things modified just to say that it is trick, My guns work as a result they are not played with just shot a lot. I have 3 SA 1911's a full size a V-10 and a Micro, all the guns will deed most any ammo I have tried. The Micro even runs fine on my hand loads of 200 grain LSWC's so none of them are messed with just for the sake of saying so.

Posted: Sun Jul 27, 2008 5:06 pm
by Bullseye
Looking at the pictures, I see an over aggressive ramp polishing. This was probably done with a Dremel and a bullet polishing tip. I wonder if the owner was having feeding problems. In any case the barrel's chamber has been opened up way past the point of supporting the cartridge case during detonation. The spent cases show the bulge deformation mirroring the ramp cut back profile. If a case blowout occurs, hot gas will be vented back downward onto the rounds in the magazine. 40 Smith and Wesson cartridges are already a hot cartridge and this type of material removal virtually guarantees a case blow out - Kaboom. This is like holding onto a hand grenade. When it goes it is not going to be pleasant for the operator of that pistol.

R,
Bullseye

Posted: Sun Jul 27, 2008 5:39 pm
by greener
Thanks. I thought "throating" had something to do with reaming the chamber to slightly increase the diameter/length when you had problems with bullet fit from the chamber being too tight or short. I thought about having something like that done to my Taurus barrel when I first started reloading because bullets that would fit other barrels wouldn't fit the Taurus. (Solved that one with shortening the OAL a smidge and a bit of a turn on the factory crimp die. )

My thought when I saw the bulge was he was lucky not to have a fist full of fire and metal parts.

Posted: Sun Jul 27, 2008 6:17 pm
by Bullseye
Throating is a common term used with 1911 smiths but it is a bit if a misnomer. The actual name should be ramp entry throating or chamber entry throating. This is a practice of opening up the chamber entry ramp width profile. It helps a cartridge feed better into the barrel chamber especially a bullet with a wider nose profile like a semi-wadcutter. The typical GI barrel ramp is cut very narrow and designed to feed .45 ball nosed cartridges. Most 1911 .45 match pistols are modified to shoot the wads to create a cleaner edged hole in the target for ease of determining shot scoring values. Match barrels usually come with a wider chamber mouth and not much entry throating is necessary when fitting these types of barrels. The barrel above is not a throated barrel and has a relatively narrow entry mouth.

The example above is actually a case of over-ramping. The barrel's feed ramp was excessively cut back into the chamber area and now the case is left dangerously unsupported.

R,
Bullseye

Posted: Sun Jul 27, 2008 6:28 pm
by greener
Thanks for the lesson.

Posted: Sun Jul 27, 2008 6:34 pm
by jaeger45
bearandoldman wrote:Maybe it was not really broke in the first place so it did not really need fixing. Some guys like to have things modified just to say that it is trick, My guns work as a result they are not played with just shot a lot. I have 3 SA 1911's a full size a V-10 and a Micro, all the guns will deed most any ammo I have tried. The Micro even runs fine on my hand loads of 200 grain LSWC's so none of them are messed with just for the sake of saying so.
I believe you hit the nail right on the head, Len.

Some fellows just don't know when to leave well enough alone.

As my dad used to say, if something don't need fixing, don't!

Posted: Sun Jul 27, 2008 8:32 pm
by bearandoldman
Saw that back in the mid 70's with snowmobiles, everyone had to alter everything they could until all they had was problems and sometimes very expensive ones. Always though that the manufacturer had more money and resources than the back alley modiifer but they kept on doing it anyway. They usually made ore noise tan andy other machine but did not perform that much better, BUT IT WAS TRICKED OUT

Posted: Sun Jul 27, 2008 11:03 pm
by greener
bearandoldman wrote:Saw that back in the mid 70's with snowmobiles, everyone had to alter everything they could until all they had was problems and sometimes very expensive ones. Always though that the manufacturer had more money and resources than the back alley modiifer but they kept on doing it anyway. They usually made ore noise tan andy other machine but did not perform that much better, BUT IT WAS TRICKED OUT
You know you are from Michigan if your truck, boat and snowmobile have V8's. :lol:

I think the rule for firearms is "If it ain't broke, Fix it." Replacement sights, trigger jobs, springs, barrels, slides...you name it. The problem is running into a gunsmith like this one who either didn't know what he was doing, or didn't care to get it right.

Posted: Mon Jul 28, 2008 10:45 am
by toyfj40
greener wrote:"If it ain't broke, Fix it."
it's always fun to 'tinker/fiddle' with my stuff...
I recall an incident when I had picked up a Marlin-60 at a pawn shop,
took it home and cleaned/greased/oiled it... and took it to the
range just to play with it... I was at a station next to a guy with
a $1000-Ruger 10/22 !! we were shooting standard targets at 50yds.
after 50-100 rounds of blowing the oil out and getting used to the
sights... feel... I was keeping a nice little grouping with my Fed#510s
... versus his "Eley" patterns...

we didn't discuss... I didn't 'make fun' (but I was laughing inside)...
he may have been doing his own thing and not worried about his pattern...
but a $75 used stock Model-60 was out-shooting his investment.
he did pack-up and leave after the next Target-change.
-- toy