Another hull separation case

[Sashaalexander]

Yesterday went to pattern my guns since i bough some new ammo and new chokes.
Used 4 kinds of ammo;
Winchester Superx 3" 1-1/4 #3
Fiocchi 3" 1-1/4 #3
Fiocchi 3" 1-1/5 #3
Kent Fasteel 3" 1-1/4 #2

Kent in 6-7 shots had 2 separations
Fiocchi 1-1/5 in 8-10 shots 2 separation

Fiocchi 1-1/4 and Win were OK for more than 25 rounds each.

This time, not as it was with Winchester which i reported about 2 month ago, there is a significant bulging of the metal part.

What can it be?

BTW, surprisingly enough Winchester was patterning the best across the board out of 2 guns with all kind of chokes.

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[pacrat]

3 ammo types, same problem sorta rules out ammo problem.

I suggest you accurately measure case head diameter before and after firing. Maybe your chamber is out of spec. allowing case head to overly expand which releases the case body from the head.

Just a possibility. Didn't read prior thread. New gun? Or new problem with old gun?

[Sashaalexander]

yes, but 1st case was clearly the ammo. As soon as i took ammo from another batch every thing was OK. Returned to the same case, 90% separations. hundreds of rounds of same Winchester(rabbit season). Than many, many rounds of Federal and Remington on the dove season. Not a single problem

Now, out of four kinds of ammo, only 2 were separating.

Yes, i thought it would be a gun, but what can it be and why not with all the ammo? Also, why the metal bulging. Looks like overload, isnt it?

The gun is fairly new, but it had close to a 1000 rounds before of various loads, mostly target, but also rem pheasant loads, and some duck loads which i patterned for turkey hunting

And i measured, the unused is .805 and used is .811. What is a chamber speck for 12GA?
And why is bulging at the primer site of the head? Chamber has nothing to do with it, has it?

PS. Just found specs for the 12GA 3# chamber diameter. it is 0.8111




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[pacrat]

And i measured, the unused is .805 and used is .811. What is a chamber speck for 12GA?
And why is bulging at the primer site of the head? Chamber has nothing to do with it, has it?

http://saami.org/PubResources/CC_Drawings/Shotshell/12-gauge%203.pdf

SAAMI says unfired dia should be .809" not .805". Your fired cases jive with the SAAMI of .811". But brass and steel plated brass spring back after firing. So your chamber is likely a bit larger than the fired case heads.

Do you have the means to measure the actual chamber dia?

So if your chamber is just a tiny bit large and your unfired cases a tiny bit small. Then the fired case at .811" - .805" = .006". Add in another .001" for springback and it becomes .007". SAAMI says it should be .002". When fired it could cause what is called "tolerance stacking". And create the seperation problem you experience.

Which could also be exacerbated if your gun is a bit fat on headspace. Or not locking up tightly. Which would contribute to the bulged base of the head. But could also be thin rims on the cases.

Keep in mind that I'm NOT saying "this or these" are your problem. I'm just mentioning all the variables that can lead to a tolerance stacking issue which could be your problem. Life is a process of elimination.

Couple all of the aforementioned variables and add some HOT 3" ammo. Bingo, head separation.

Headspace on shotguns is measured on the rim. Look at the SAAMI link provided. Noting the rim thickness @ .576" with a minimun of -.014" for a true minimun of .562". A .014" OA tolerance or +/- .007" of the median headspace.

I suggest you try this..........Regular old brown masking tape averages .005" in thickness. Place varying layers on the base of some of the troublesome ammo. Trim flush outside and around the primer hole. If you can put 3 layers of tape or more [count them] and your gun will still close and lock up. You gun has loose headspace......or the ammo is undersized on the rim. That will give you a comparator of gun headspace and rim thickness with the troublesome ammo. And tell you using the SAAMI dimensions if that is a contributing factor to your problem.

Sorry but simple questions sometimes have complicated answers that require some experimentation to ascertain true cause.

Most likely, you will just have to be very picky about which ammo you buy for this particular shotgun.

Have you yet tried ammo made with a one piece case body without a separate base wad?

[JagerDog]

http://saami.org/PubResources/CC_Dra...-gauge%203.pdf

SAAMI says unfired dia should be .809" not .805". Your fired cases jive with the SAAMI of .811". But brass and steel plated brass spring back after firing. So your chamber is likely a bit larger than the fired case heads.

0.805 is right in the middle of tolerance (0.809 +0.000/-0.009).

TMK plating doesn't affect springback. Brass springs back more significantly than steel (be it plated or in the white). Some tube mfg's recommend only brass based hulls to eliinate sticking in chamber.

I don't have direct experience with OP's shells. I've shot a lot of 3" 20g Fiocchi and my skeet partner shoots a lot of 2-3/4 12g Fiocchi. I havn't witnessed either one seperating. He had significant seperation issues with reloaded 28g Fiocchi hulls.

[Bt Doctur]

Are you sure you have a 3 inch chamber?

[Sashaalexander]

Here are some answers:
"Are you sure you have a 3 inch chamber?" :-). Yes, otherwise how i was shooting other ammo

The chamber diameter is 0.812 in this gun and 0.813 on another which does NOT have separations., so, not the chamber dimensions.

The base diameter on the Kent is 0.805. - Separating
Fiocchi 1-1/5 0.802 - Separating
Fiocchi 1-1/4 0.802 - NOT separating
Winchester 0.801 - NOT separating

So, not the base diameter as well.

Now about the head space.

I put shells, all of them one by one in to the disassembled barrel. All of them are even with the brim. none of them protruding or significantly inside.

Tried your method. I cannot tell on the semi-auto if it locks or not. It is not a bolt action. Is there any indication? Looking at the bolt construction on both guns, it will lock even if i put there a 1MM shim.


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[JagerDog]

Here are some answers:
"Are you sure you have a 3 inch chamber?" :-). Yes, otherwise how i was shooting other ammo

The chamber diameter is 0.812 in this gun and 0.813 on another which does NOT have separations., so, not the chamber dimensions.

The base diameter on the Kent is 0.805. - Separating
Fiocchi 1-1/5 0.802 - Separating
Fiocchi 1-1/4 0.802 - NOT separating
Winchester 0.801 - NOT separating

So, not the base diameter as well.

Now about the head space. I use this method for bolt action guns, but how I can tell exactly when the Semi auto bold locks. Is there any way to tell the exact point?


I put shells, all of them one by one in to the disassembled barrel. All of them are even with the brim. none of them protruding or significantly inside.

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Well..3" shells will fit in a 2-3/4" gun, but the crimp portion can cram into the forcing cone when fired.

[Sashaalexander]

Well..3" shells will fit in a 2-3/4" gun, but the crimp portion can cram into the forcing cone when fired.

You are absolutely right, but:
1. It is stamped on the barrel.
2. I measured the chamber length because at the beginning i thought maybe the chamber is too short despite the stamping. It was my first thought even before i wrote here.
3. if you read my post, on the same day only it ate more than a hundred 3" shells successfully not to mention some before.
4. it is a 3" contemporary semi-auto gun. I do not recall any semi-auto gas operated guns manufactured in the last 10-15 or more years with less than 3" chambers, do you?
5. I'm not a first day hunter, i have more shotguns in my safes :-), it is true, i do not know much about shotguns, but i know this much for sure, it is a 3" chamber.

[pacrat]

JD said

0.805 is right in the middle of tolerance (0.809 +0.000/-0.009).

oopsy, I'm always reminding people of +/- tolerances and while flipping back and forth from site to site, between typing and looking at drawings missed the obvious. Thanks JD.

OP with pump guns, if it doesn't lock, the slide will easily retract. If locked, you have to either fire it, or hit the slide release to open it.

With semi, it takes definite "tug" on handle to unlock and open opposed to easily opening due to not requiring the force to unlock. Determined by feel.

Is there any common factor as to case construction? One piece plastic, opposed to separate base wad?

[JagerDog]

You are absolutely right, but:
1. It is stamped on the barrel.
2. I measured the chamber length because at the beginning i thought maybe the chamber is too short despite the stamping. It was my first thought even before i wrote here.
3. if you read my post, on the same day only it ate more than a hundred 3" shells successfully not to mention some before.
4. it is a 3" contemporary semi-auto gun. I do not recall any semi-auto gas operated guns manufactured in the last 10-15 or more years with less than 3" chambers, do you?
5. I'm not a first day hunter, i have more shotguns in my safes :-), it is true, i do not know much about shotguns, but i know this much for sure, it is a 3" chamber.

1) New information
2) New information
3) Anecdotal (and no, it is not clear that all functioning shells were 3").
4) You might be surprised how many semi-autos were made for max 2-3/4" shells. Some models have a "magnum" counterpart for the use of such. Also new information.
5) New/anecdotal information.

Your previous assertion that it was suitable for 3" shells was that they chambered/fired.

[Sashaalexander]

1) N
3) Anecdotal (and no, it is not clear that all functioning shells were 3").

Seriously?, maybe have a look at my original post?

4) You might be surprised how many semi-autos were made for max 2-3/4" shells. Some models have a "magnum" counterpart for the use of such. Also new information.

Interesting, could you please list at least 2 contemporary hunting semi gas operated with 2 3/4 chamber?(made in the last 10 yars or so and not custom

Your previous assertion that it was suitable for 3" shells was that they chambered/fired.

What is it about? Just to make a stupid of me or to show how smart you are?

[JagerDog]

Seriously?, maybe have a look at my original post?


Interesting, could you please list at least 2 contemporary hunting semi gas operated with 2 3/4 chamber?(made in the last 10 yars or so and not custom



What is it about? Just to make a stupid of me or to show how smart you are?

1) You did not state the barrel was stamped 3"
2) You did not relate that you had confirmed via measurement
3) You gave more detail about some shells than others.
4) Is a Remington 1100 (non-magnum) contemporary? How about a Franchi 48AL (no longer in 12g it seems)? Browning Silver Sporting?
5) Rather to indicate your lack of communication and how Bt Doctur's question was still valid while also indicating that the verification (chambered/fired) was irrelevant to answering his question.

[Thefeeder]

><

Sasha...I'll be at Sunnyvale R&D tomorrow...bring it by and lets take a look at it.

Most likely your going to be hunting.

[Sashaalexander]

Luigi,
No, i never go for opener,(including dove LOL..) hunting is for joy. Opener is not.
I'm going on Tuesday and Thursday next week. maybe also Friday if ducks cooperate.

What time are you gong to be there? I'll see what my best half's plans.

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