Help identifying this damage(?)

[Ranch Dog]

You can get a dial caliper at Harbor Freight for $20. You can always find coupons to go with the purchase, maybe not dollars off but a coupon for a free tape measure, screwdrivers, etc. with the purchase. By a dial caliper, not a digital one.

[Bisleyblackhawk .45]

I'll agree with RD on this...I don't see that small of an area causing issues. The part of the cartridge case that rests in and is supported by that part of the chamber will be the case web where the inside of the case gets thicker as it transitions into the rim...I'll be surprised if your cases will show any ill effects. If you look at a case fired in a Glock or Makarov, both of which have generous unsupported areas in their chambers, you can see a big expanded bulge way past the web...I don't see anything that extreme from your photos that would bulge your fired case much less result in a ruptured case. But it would be easy to check with a micrometer.
There is nothing that a cartridge feeding in off the lifter can do to make that small section worse over time.

If it were mine and I found a cartridge that worked reliably, would I worry about it?...nope...I would just shoot and enjoy it.

[Ohio3Wheels]

Will do next range day (friday hopefully! Thankfully wifey loves to shoot too) but i need to buy a micrometer

In anycase lets say theres no bulging in the case, will this issue have any effect on my rifle over the coming decades? I dont think ammo should be an issue as i suspect lead nosed or even jacketed rounds wont cause further damage (?)

I don't think you have a problem there and as long as the fired cases don't show anything funky I'd follow the advise of the guy on the CCI 22 boxes "just choot 'em" and have fun. A lever gun and a bucket of ammo along with a wife that likes the smell of gun powder is hard to beat.

Make smoke,

[dlidster]

I'm another who believes you have nothing to worry about. This chamber work is pretty typical. On the plus side, the alignment of the extractor groove in the barrel with the extractor groove in the receiver is perfect. This is unusual. Typically the grooves are out of alignment. (Mine are and it annoys the heck out of me.)

Count yourself lucky and enjoy the gun.

[Smoke4320]

I agree nothing looks out of wack ..
Fire 4 or 5 rds and look for any bulging in the case
if none no worries mate

[GRV01]

Thanks all for the tips and pointers. This rifle is my first firearm purchase ever amd i really want it to outlast me. Honestly i feel like a new parent, every cough or sniffle gets me in a tizzy about something being seriously wrong when i really just need to calming advice of an older parent or grandparent to tell me "relax and just give them a little whiskey!" Kidding but you get it

Ill take a bunch of cases to work and use a co-workers calipers to test, but like many of you i suspect itll be fine. Cant wait to hit the range next week!

[Centaur 1]

From what I can see, I think it's fine. You have a flat surface, intersecting with a cylindrical hole at an angle. It doesn't take much to make it look a little off. When they cut the groove for the extractor, it probably created a burr in the chamber that had to be filed off.

[Pops]

I shoot my Rossi 92 a lot 200-300 rounds a month the bulge is on almost all of my cases. I reload my own and this is what I now do I decap the cases with a universal decapper then clean the cases resize the cases with a steel RESIZE ONLY die ( RCBS) less taper then a carbide resize/decapper die or steel steel/decapper die it removes the bulge. I also switched to a slower burning powder H-110 and 158 bullets ( same bullet I was using before) and lighter loads at 9gr cartridges are a bit dirty at 10gr, 11gr and 12gr they get cleaner as I increased the load no bulges so far. Going to try a faster burning powder wher the H110 is gone I don't like a 1/2 black ejected cartridge at my feet.
The bulge is from the unsupported part of the chamber where the round first enters the chamber I have a Ruger 77/357 that does the same thing for the same reason.

[GasGuzzler]

In my experience slower magnum powders don't like to be downloaded at all and 9 grains H110 in .357 for a 158 gr bullet is only 60% of the START load for H110.

I'm not keeping a .357 firearm that won't shoot a 16 gr load of H110 under a 158 bullet.

[mr surveyor]

I've never used H110 or W296, for just that reason. I believe the warning is not only on the powder container, but in most all reloading books to NOT download those two powders below the (legitimate) load data recommendations.

Pops, I'd recommend you stay very closely within spec on the H110. If you want something to play
up and down", Unique works very well.

And the "dirty" is nearly always caused by incomplete combustion due to undercharging (and that goes for the "dirty" in Unique as well)

jd