Home Forums Reloading Big Game Rifles Tight chamber and pressure?

I don’t have a headspace comparator, just an ogive one. Trying to keep things simple. I’m kinda new at reloading but have not had these problems with a couple other rifles before.

I wouldn’t worry about shooting factory ammo, so long as it chambers.

You shouldn’t have to resize brass to chamber if it’s to spec. If the chamber is so tight that you can’t chamber factory ammo and/or new brass, ammo and brass that’s within SAAMI spec, I’d be fixing the chamber.

Did you verify throat jump—just to be sure you’re not headspacing off the bullet. Is the chamber and throat clear of chips/debris? Do you have a borescope?

You might be able to use your bullet comparator to compare HS dimensions on your brass, if you have the .416 insert.

I don’t. .358 is biggest I’ve got.

Yeah, there’s lots of throat. These loads were all .080”+ out. PacNor said they have an inspection process before shipping so I’d assume they scoped it.

I’ll get some new brass and some factory ammo and see if it chambers.

Look in the chamber real good with a flashlight and see if you’ve got a stray chip or bit of swarf swaged in there.

I did that, and cleaned and dried it well. Appears all clear. Nothing obvious.

No problem there, remember that neck has contracted after it released the bullet, from the sound of what you are say it is a nice neat chamber as one should expect in a custom barrel
You really need to do your load workup in conjunction with a good chronograph, the magnetospeed has worked really well for me

sdhuntr...I have a Forster case trimmer..I`m sure you have a simular tool, in which I can place a carbide cutting tool which is about 2 thous over bullet dia. What that does is uniform the necks on cases of various manufacture that may be a bit thick. So a bullet can be inserted into a fired case with no pressure at all. Whoever manufactures your trimmer should offer them. Get one.

I think you may be assuming your handloaded ammo is lacking in velocity, cause if I understand you, you can`t test this yet? Don`t jump to conclusions till your sure. All my PN barrels gave me the vels I wanted, below listed max in the books.

Your rifle is new....work with it till you understand what it`s telling you.

I would say yes..PN`s QC is SOP.

Good luck

Just a thought, don't know if it applies to sdhunter - I've seen fired cases sometimes that look like they have a little bit of crimp; i.e. the case mouth is tighter than the rest of the neck. That happens when case length is slightly long for the chamber, and it can raise pressure a bit.

I've also encountered a chamber or two that had shorter necks than standard spec, so cases trimmed to spec could still end up being too long. That can be hard to identify if you don't know to look for it.

Well the saga continues. Drove 30 miles out of town to the only decent gun shop around. Bought a new box of Lapua brass. Same thing, it won’t chamber. Bought a box of Barnes factory ammo. Guess what, it won’t chamber either. Man I was really hoping I just got a batch of bad brass at first. Now I’m really pissed! Now I have to take the scope off and ship back up there. Then sight in all over again! Arrghhh!

Yondering,

Have seen that as well, in fact my custom 6.5 SPC needs to have cases trimmed slightly shorter than SAAMI specs or there's some tightness inserting bullets into fired necks.

Don`t think anyone asked, did PN do the barrel job for you, install, or a local smith?

Either way, they should stand behind the work done.

That sucks..

Although a PIA in the short term, this is the right move.

I'm finding this thread to be very interesting. I have a custom rifle based on an FN commercial Mauser chambered to the 7x57 that has a very tight chamber. Like the OP, I get high pressure signs before reaching maximum published data. I haven't been able to set my chronograph up since the range changed the rules so I have no idea what the velocity is. Now that we're getting our summer thunderstorms on a fairly regular basis the range is a bit of a mud hole anyway with all the eater running into the 100 yard line and backing up to the berm.

To give an idea of what's happening, I loaded up some 170 gr. Sierra round nose bullets to duplicate the original 1893 load and then shot them over the chronograph. The Ruger #1A did 2310 FPS, the M70 FWT a bit faster at 2320 FPS and the custom Mauser 2450 FPS. I talked with my gunsmith and asked if he'd done a shorter than the usual throat and he said it had the long throat suited to 175 gr. round nose bullets. Twist is 1 in 8.5" BTW. Dunno for sure what the Ruger and Winchester have for barrel twist rates.

Guess I'll have to check if the bullet slides easily into the case next time out.
Paul B.

Will it chamber new brass without resizing?

take that rifle back to the gunsmith and all your different ammo, i bet the no go and go gauges don`t work either. sounds to me that gunsmith did a very poor job of machining that chamber on that barrel.

Yes, a chronograph. You do not know that your loads are anemic until you measure actual velocity.

All smiths I`ve had work done barreling a rifle, produced at least three fired cases for me after test firing the gun. You should have gotten the same.

That didn’t happen in my case. It’s frustrating, and an inconvenience to have to ship back, But we are all human beings. [bleep] happens. Pac nor has assured me they will make it right. I’m going to give them that opportunity before I badmouth them. Fingers crossed.