Should I be worried?

[Tiny Tim]

I doubt you have damaged your rifle, but a competent smith should be capable of inspecting it for a relatively small fee. You don't mention what your sizing issue was, but suspect that you have been full length sizing and head spacing off the belt rather than the shoulder. JE has given a great explanation in the past about the use of the belt for reliability for these belted cartridges. The problem becomes that this method of head spacing stretches the case repeatedly above the head with each reloading cycle and results in case head separation. If this has been you error in sizing, get some new brass and start with that and only bump the shoulder back as required after the first firing and you should be good to go..

 

[kfreeze]

No I am starting with slightly lower than starting loads and working up

Don't go under the min loads in a book. The min is there to protect you too.

 

[Bob Wright]

If you are loading under book minimum, it can be disastrous. "Bridging" or simultaneous combustion of most of the powder is a massive spike in pressure.
Just stay above by a grain and work up to max.
Head separation is usually head space errors. Belted mags when new, headspace off the belt. Once!
After a few firings, each brass should stretch to the shoulder datum of your chamber. The shoulder datum should be checked on each brass before reloading. If they vary more than .003, you're not there yet. Anneal them at the neck/ shoulder, full length size without bumping the shoulder (measure!). Check for fit.
Those should now give you a final headspace number after firing within .001 of each other. My 7RM cases stretch .019 on first firing at the shoulder datum. It's normal.
This cartridge family, yours/mine were dangerous game designs where each cartridge is guaranteed to chamber and eject by basing the headspace of the belt first.
Start measuring, look for bright rings above the belt, use the paper clip feeler internally to feel "under cuts" and/or start over with new brass.

 

[CVCOBRA1]

Have you checked case length? After five loadings they are probably long too and need trimmed. I would toss those cases and start new myself. More than likely no damage done if you got the rest of the case out that easily.

 

[Hoppsing55]

I'm fairly new to reloading and still learning quite a bit as I go. Recently bought a new Savage 110 chambered in 300 win mag. Worked up a load with some R19 that was pretty decent but with less than favorable results and the difficulty in finding powder currently I've switched to H4350. I've been using the same brass for several reloads and have recently discovered I've been resizing incorrectly the entire time. Now on to my concern. I worked up a load of 69gr of H4350 with federal 215 primers pushing a 168 Nosler E Tip. I shot 3 rounds that resulted in a slightly heavy bolt lift and a little more force needed to work the bolt than normal. But not excessive. Other than that no high pressure signs and everything else looked fine. Regardless I did not shoot the rest of what I had loaded. Went home and pulled them. Reloaded some with a slightly lower starting load. First round seemed fine. Chrono read just under 3000 FPS. Second round spiked at 3028. Bolt lift wasn't excessive but I had to almost literally beat the bolt back for extraction. The case completely separated right above the belt and the rest of the brass was stuck in the chamber. Primer looked fine. I didn't mess with it at the range just packed up and left. When I got home which was in about an hour I was able to use a .410 bore brush and remove the case with zero effort. Got a factory load. Chambered fine. Shot a round in the backyard (very rural) and it extracted just fine with zero high pressure signs. I have since discontinued all the old brass I was using and am about to start working up loads with all new brass. I've also read about the error of my ways in regards to resizing and chamber length.

My main question is what are the odds I've done damage to my chamber or barrel I can't see? I've cleaned both thoroughly and see no visible signs of damage. The bolt looks fine. No imprinting on the face. Extractor works as it's supposed to. Any help or insight is appreciated. Thank you

Can you explain what you mean: "I've been resizing incorrectly"? Please elaborate.

 

[SouthernWinMagShooter]

Can you explain what you mean: "I've been resizing incorrectly"? Please elaborate.

Setting a FL sizing die as you normally would for a non belted case. I've since learned the error of my ways.

 

[WYO300RUM]

I didn't mean it to sound like start below min.. To start at min. My bad.

 

[Hoppsing55]

Setting a FL sizing die as you normally would for a non belted case. I've since learned the error of my ways.

OK. So it sounds like there was a little excess "bumping" back of the shoulder. Multiple shootings allowed the brass to stretch and migrate forward of the belt, (thinning the wall) depositing around the shoulder and up into the neck. Creating the "sticking" effect you experienced. It does not sound like you have "over pressured" the chamber.

 

[WYO300RUM]

I didn't mean it to sound like start below min.. To start at min. My bad.

I looked . Wise advice. At least from my experience .

 

[corsteve]

try annealing brass an see what that does

 

[vancewalker007]

I'm fairly new to reloading and still learning quite a bit as I go. Recently bought a new Savage 110 chambered in 300 win mag. Worked up a load with some R19 that was pretty decent but with less than favorable results and the difficulty in finding powder currently I've switched to H4350. I've been using the same brass for several reloads and have recently discovered I've been resizing incorrectly the entire time. Now on to my concern. I worked up a load of 69gr of H4350 with federal 215 primers pushing a 168 Nosler E Tip. I shot 3 rounds that resulted in a slightly heavy bolt lift and a little more force needed to work the bolt than normal. But not excessive. Other than that no high pressure signs and everything else looked fine. Regardless I did not shoot the rest of what I had loaded. Went home and pulled them. Reloaded some with a slightly lower starting load. First round seemed fine. Chrono read just under 3000 FPS. Second round spiked at 3028. Bolt lift wasn't excessive but I had to almost literally beat the bolt back for extraction. The case completely separated right above the belt and the rest of the brass was stuck in the chamber. Primer looked fine. I didn't mess with it at the range just packed up and left. When I got home which was in about an hour I was able to use a .410 bore brush and remove the case with zero effort. Got a factory load. Chambered fine. Shot a round in the backyard (very rural) and it extracted just fine with zero high pressure signs. I have since discontinued all the old brass I was using and am about to start working up loads with all new brass. I've also read about the error of my ways in regards to resizing and chamber length.

My main question is what are the odds I've done damage to my chamber or barrel I can't see? I've cleaned both thoroughly and see no visible signs of damage. The bolt looks fine. No imprinting on the face. Extractor works as it's supposed to. Any help or insight is appreciated. Thank you

The same thing happened to my STW years ago. It's like just a case separation from pushing the shoulder back too far when resizing. You didn't hurt you rifle. Also your brass is likely work-hardened if you have shot it 4 or more times without annealing it. I'd get some fresh brass and get that die set to bump your should no more then .002 in. You may want to back off you load some and ease back up .2 or .3 grains to find some velocity nodes.