Thread: 7mm-08 reloads extraction issue - thoughts please

Thks team for the later info and suggestions, will get on to it.

Doesn't sound like an ammunition problem.
If the bolt lifts all the way up, the case should come out freely after this. Lifting the bolt up all the way should engage the primary extraction and should move the cartridge back a mm or two. It should then pull easily back.
Sounds like the rifle is missing primary extraction, or the extractor isn't working properly, take it back if it's new.

This might not have been a problem for factory rounds as they may be a bit less pressure, but with hand loads loaded closer to max the brass is expanding a bit more and sticking to the chamber walls a bit, primary extraction should be sufficient to provide you the mechanical advantage to get the case moving. Pulling the bolt handle back should be just removing an already extracted piece of brass from the chamber to eject.

Originally Posted by Makros

Doesn't sound like an ammunition problem.
If the bolt lifts all the way up, the case should come out freely after this. Lifting the bolt up all the way should engage the primary extraction and should move the cartridge back a mm or two. It should then pull easily back.
Sounds like the rifle is missing primary extraction, or the extractor isn't working properly, take it back if it's new.

This might not have been a problem for factory rounds as they may be a bit less pressure, but with hand loads loaded closer to max the brass is expanding a bit more and sticking to the chamber walls a bit, primary extraction should be sufficient to provide you the mechanical advantage to get the case moving. Pulling the bolt handle back should be just removing an already extracted piece of brass from the chamber to eject.

what he said

No, my dollar is on excess headspace, as I've had this issue but with a different make of rifle (Rem M7).
@Jhon , remove firing pin and place a single strip of masking tape over the back (case head, where primer is). If the round still chambers, you have the answer.

Solution is either use the elongated (sticky) cases that have come out of the rifle, but suffer shorter case life, set the barrel back or return to point of purchase with headspace gagues as proof.

Originally Posted by caberslash

No, my dollar is on excess headspace, as I've had this issue but with a different make of rifle (Rem M7).
@Jhon , remove firing pin and place a single strip of masking tape over the back (case head, where primer is). If the round still chambers, you have the answer.

Solution is either use the elongated (sticky) cases that have come out of the rifle, but suffer shorter case life, set the barrel back or return to point of purchase with headspace gagues as proof.

Ok, excuse my ignorance but why remove the firing pin? Won't it be retracted into bolt on cocking as brass is chambered? Educate me...

Greetings,
I am pretty sure the problem in not head space. The quoted loads are pretty stiff so the cases will be expanded to snugly fit the chamber. Very light loads can produce extraction issues if the cases are under size to start with or the chamber has excessive headspace. The pressure is not high enough to fully expand the brass. This is not the case here. Reducing the load to 42 grains for the SST projectiles may help as this will slightly reduce the case expansion.
GPM.

Thanks GPM, reducing the load is first cab off the rank

Originally Posted by grandpamac

Greetings,
I am pretty sure the problem in not head space. The quoted loads are pretty stiff so the cases will be expanded to snugly fit the chamber. Very light loads can produce extraction issues if the cases are under size to start with or the chamber has excessive headspace. The pressure is not high enough to fully expand the brass. This is not the case here. Reducing the load to 42 grains for the SST projectiles may help as this will slightly reduce the case expansion.
GPM.

Yes I cant see this being caused by head space either. It is often an issue with the die/chamber relationship. The chamber being on the tight end of the spec and the die on the larger. I talked this through with Harvey Westland some decades ago. Reducing the load should have a positive effect but depending on the tollerances the problem could raise its head again after a few more reloads on the brass depending on the pressure. In Harveys case it was with one of his Bench rest rifles, he checked his dies with pin gauges and tried 4-5 different sets till he found one that would size his cases enough to function reliably at the loads he wanted to run. I sent him a rifle of mine that was also having this issue and he reamed out the chamber wall by a couple of thou which fixed the problem . Iv also used a small base die to good effect in these situations.

Small base dies if you can get them, but the other issue might be a good annealing of the brass. As stupid as it sounds, that might be a cause of this. I had it in an old zkw465 .22 Hornet - hardly something you can get hot loads in! Factory ammo, fine, once fired first reload fine as well. Second and subsequent firings, every second mag at least one would stick and need to be popped out with a cleaning rod. Annealing helped for another couple of reloads.

Part of the issue with it I suspect is the modern dies are a slightly different profile to the early Euro spec chamber and don't quite resize enough. The was no issue with the chamber or action on that rifle, so there may not be on this one either. I would suggest the third firing thing is a coincidental thing and not witchcraft.

A few thoughts.

Does he use WD40 or any other CRC spray can lubricant? Some of this stuff forms a sticky film in the rifle. It can gall up firing pin.

I would give the chamber a good clean & wipe with 3 patches of tissue paper & alcohol.

The giveaway is the case coming free after waiting a few minutes. That to me is soft case expanding with hot load, then when it cools down it releases enough to extract. Ive had it before.

You can try different brass. I used to get that with a .270 when I used Fiochi brass and the time honoured 60 grains of H4831 with 130g SP. Changed brass brands and all fine. Same velocity and accuracy.

I have a 308 with similar issue. I backed the load off till it was stupid slow thinking it was too hot but still had the same problem. In the end it was a headspace issue. My chamber is short. Possibly shorter than SAMMI spec. The problem was solved with FL sizing everything hard. Does factory ammo extract ok? It's a fairly full load at 43g.

Just a thought.

Did you measure all the key data points of the fired cases and compare them? Did anything stand out? How much did the problem case stretch in length and at the base web?

Originally Posted by Nakihunter

Just a thought.

Did you measure all the key data points of the fired cases and compare them? Did anything stand out? How much did the problem case stretch in length and at the base web?

Its been on hold until we can get together after.mate had a family bereavement. Elderly person passed so sad but not unexpected. Anyway we are planning on remaking some loads this week. Test them next week. Will measure everything lol

UPDATE.

So sometimes the simplest things are a great place to start. We remade the last x16 rounds. Pulled the projs, dumped and collected the powder, FL sized the cases just to be totally sure, re-seated the primers, re-loaded the powder charge reduced by 0.2gn and re-seated the projectiles to same depth. Then we went out yesterday and collected goat tails. With goats like maggots on a carcass, mate could take a prone position and empty his 3 round mag with consecutive strings. No extraction issues experienced.

So on reflection, as suggested above, the difference in seated depth of the 139gn SST projectile vs the 139gn SP Flat Base may well have been the issue with just tipping the pressure to a level that in this rifle caused the action to somehow lock on the 3rd shot in string until cooled a bit. Which does suggest a mechanical issue either with the action/bolt design or a flaw of some sort in this rifle.

In the end, we found a reliable and accurate load doing the job no issues. And man can those SSTs rip a body up?