Sig P365 chamber support
- Thread starter jski
- Start date
CapnMac
Member
Photo of mine
CapnMac
Member
Depends on who you ask. Some will call that "dangerously unsupported" others will call that fully--the internet is weird that way.
Note that there's about 3-3.5mm of case head in a 9x19 that's functionally solid.
The SIG barrel pretty much aligns with the case groove so that the extractor on the breech face can engage.
In my book, that's "fully supported."
There are internet flame commandos who will insist otherwise, though.
sparkyv
Member
I'd call that pretty well supported. No bulges in any of my rounds either, though I've not put 2k rounds through mine (yet).
Fully supported is in a cylinder on a wheelgun but does any autoloader provide that level of support?Depends on who you ask. Some will call that "dangerously unsupported" others will call that fully--the internet is weird that way.
Note that there's about 3-3.5mm of case head in a 9x19 that's functionally solid.
The SIG barrel pretty much aligns with the case groove so that the extractor on the breech face can engage.
In my book, that's "fully supported."
There are internet flame commandos who will insist otherwise, though.
halfmoonclip
Member
- Joined
- Feb 4, 2011
- Messages
- 2,769
No bulges on the 9mm brass that's been through a 365. I've tried some +p; the gun will run it, but it isn't any fun.
I'm getting a chronoed 1100'sec with handloads, Blazer Brass, and SIG 365 ammo, so no need to go all out.
Moon
I'm getting a chronoed 1100'sec with handloads, Blazer Brass, and SIG 365 ammo, so no need to go all out.
Moon
Just trying to establish what the 2 endpoints of this spectrum are.
It appears that what’s considered fully supported versus what’s considered partially supported is vague.
Last edited:
I have stood next to someone with a Colt Delta Elite chambered in 10mm shooting some “spicy” loads and got sprayed with brass shards when it experienced almost complete case head separation.
That’s was when I first became aware of this issue.
That’s was when I first became aware of this issue.
Since people shoot Colt Delta Elites all the time without having case blowouts, I think it's safe to say that you experienced some kind of an ammunition problem.
It's not difficult to understand why manufacturers do not make guns with so little chamber support that they will blow cases with properly loaded factory ammunition. This gets back to my original comment. If you are seeing bulges on your handloads, then back off your loads. If you are seeing bulges on factory brass then you need to be cautious about loading hot loads for that gun and about re-using cases fired in that gun since if you have to significantly resize the brass all the way down to the case head every re-use it is going to fail a lot sooner than normal.
If you are not seeing bulges then your question is academic.
Fully supported is usually taken to mean that the "non-solid" portion of the case is supported. Anything else is partially supported. Obviously there are no "fully unsupported" chambers.
Looking at the diagram provided in post #5 shows that the case walls taper thicker as you get closer to the case head, so it's not hard to see that one might be able to get away with stopping the support a little before you actually get to the "solid" portion of the case as long as pressures are not too high. "Not too high" depends on the cartridge in question.
This obviously creates the possibility for some interesting differences of opinion, especially for people who aren't interested in looking at case diagrams and can only tolerate it if things are either black or white. In practice, if you are not getting case bulging then it really doesn't matter. Even some case bulging is not a big deal if you are not reloading your brass.
Why not always provide full support? Feeding in an autopistol generally works better when some of the chamber is removed to allow the case to slide more smoothly from the magazine into the chamber. Some manufacturers take this farther than others and some designs require more than others.
I do not know whether the round was a factory or hand load but I do believe that Delta Elites are categorized as partially supported.
If you are asking whether the level of chamber support in the pistol in question contributed to the incident, here's my opinion: It's not difficult to understand why manufacturers do not make guns with so little chamber support that they will blow cases with properly loaded ammunition. I think it's safe to say that the incident was likely due to an ammunition problem. It's possible that a gun with more chamber support could have handled the failure differently, but when brass starts failing, there's a lot of energy involved and the tiny bit of steel missing from where the feedramp is probably won't make a lot of difference.
So, leaving the full-sized 10mm Colt and getting back to the subcompact SIG 9mm you asked about...
1. Are you having issues with the P365 bulging brass?
2. Have you seen claims that the P365 bulges brass?
3. Is it your plan to load or buy ammunition for the P365 that exceeds SAAMI specs for 9mm +P?
If the answer to all of these questions is "No", then, in your position, I would find something else to concern myself with.
So, leaving the full-sized 10mm Colt and getting back to the subcompact SIG 9mm you asked about...
1. Are you having issues with the P365 bulging brass?
2. Have you seen claims that the P365 bulges brass?
3. Is it your plan to load or buy ammunition for the P365 that exceeds SAAMI specs for 9mm +P?
If the answer to all of these questions is "No", then, in your position, I would find something else to concern myself with.
DITTO! My experience with many 10mm shooters is they also like to “hot-rod” their loads. I know one guy that is getting 1300+ from a 210gr cast bullet… I’m not that brave(or foolhardy, or just plain stupid… pick the adjective you prefer) And I’ve resized some of his cases! Not good…
Last edited:
As posted, the part of the case head that shows outside the chamber is solid, if you bulge or blow that up, it's not the gun's fault.
Completely irrelevant to the P-365 question.
A reloading problem, not a gun problem
I would beg to disagree. After that experience, it became apparent that some ammo may work fine in some autoloaders but may not work so fine in other autoloaders and you need to know which ammo works for the gun you may want. The P-365 is a particular case (pun not intended) of interest for me.
The Delta Elite is a fine handgun and I’m not questioning that but the person firing it should have been aware of what ammo worked with his handgun.
Last edited:
red rick
Member
- Joined
- Aug 11, 2009
- Messages
- 3,154
That is a question that I would have asked him .
True, but to be relevant it has to be an apples to apples comparison with similar chambers offering the same support. It also has to be similar ammo, and not over pressure ammo in either.
I don’t know that it was a handload but what I do know is that it was an excessive pressure load for that handgun. Just trying to establish what that might be for the P-365
A case head separation may be due to an overload, overpressure ( possibly from bullet setback), firing out of battery or weakened case. Usually, the question of fully supporting the chamber relates to relief for feeding. I would expect any issues associated with that to blow the mag out of the gun before lateral dispersion of brass/unburnt powder.
As previously noted, in today's clickbait world we would be awash in dire anecdotes if this was an issue for the p365.
As previously noted, in today's clickbait world we would be awash in dire anecdotes if this was an issue for the p365.
Similar threads
- Locked
