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

Originally Posted by caberslash

If you are wondering why the cartridges chamber OK but difficult to extract... physics textbook and the bit about Archimedes and levers/leverage.

After the case has fired, you don't always get sufficient brass springback if the fit was tight to begin with.

Well I did abandon physics in Form 6 as neither my head nor my math was up to it, but happy to take you word for it. The dealer agrees with you and in a nutshell offered the the 3 lug bolt design found on the Ruger, and other rifles, is inclined to produce this extraction issue when, like you say, brass is resized enough to chamber but not sufficiently at the last few mm of the base which expands to cause a bind. A 2 lug like a Mauser design has a lot more extraction power, apparently. So the fix according to the dealer is to look for issues like the press is not sufficiently anchored to prevent "bounce" and incomplete FL sizing, operator error, slightly overspec dies. He didn't say but probably case brass variations also. Anyway, he is lending me a set of used Hornady dies to try something different. Not having a small base die. After that it will be sending some off to @sneeze to run thru his. We are marking the cases that won't extraction until they cool.

Interesting problem. Thanks for all the input. Will update.

Greetings @Jhon and all,
A couple of observations that may not have been covered. First the 129 grain Hornady projectile is noted as being soft and needs a little more powder to develop the same velocity. From your OP I gather these gave no problems. From my measurements the 139 grain SST is around 2mm longer so may develop a little more pressure due to the reduced case volume. Hodgdon lists 42.2 grains as max for the 140 grain A Frame and Nosler lists 42 grains for their generic 140 grain data. This leads me to believe that 42 grains may be a more sensible max for the SST projectiles. The likely lack of primary extraction has been well discussed and may be inherent with the rifle. This leaves the cases. Each time a case is sized the worked section of the brass becomes a little harder. The same thing happens when it is fired. This may explain the return of sporadic problems with case sticking.
Hope this helps. GPM.

Pretty interesting thread.

I would be considering taking a press to the range, using one case and measuring it at 5 or 6 points both before firing, after firing and after resizing and reloading it until it sticks.

Maybe using one that's stuck before as a start point? Just see if there is a point in dimensions where you start having the issue, and then you can compare the chamber and case specs from SAAMI and see if you can identify a discrepancy.

Originally Posted by Jhon

Well I did abandon physics in Form 6 as neither my head nor my math was up to it, but happy to take you word for it. The dealer agrees with you and in a nutshell offered the the 3 lug bolt design found on the Ruger, and other rifles, is inclined to produce this extraction issue when, like you say, brass is resized enough to chamber but not sufficiently at the last few mm of the base which expands to cause a bind. A 2 lug like a Mauser design has a lot more extraction power, apparently. So the fix according to the dealer is to look for issues like the press is not sufficiently anchored to prevent "bounce" and incomplete FL sizing, operator error, slightly overspec dies. He didn't say but probably case brass variations also. Anyway, he is lending me a set of used Hornady dies to try something different. Not having a small base die. After that it will be sending some off to @sneeze to run thru his. We are marking the cases that won't extraction until they cool.

Interesting problem. Thanks for all the input. Will update.

If the dealer is admitting something is wrong (which there clearly is), then they have to either fix it for you or replace/refund.

Had to deal with my fair share of professional shysters in the UK selling second-hand rifles, honestly second-hand car dealers are more reliable and trustworthy. Once got sold a rifle with an under-sized chamber (someone rechambered from 222 to 223, and did a poor job), then a 7mm-08 where the idiot had replaced the bolt with a crap PTG unit and fucked the job, due to the fact the locking lugs did not match those of the original bolt, leaving excess headspace.

The situation you are in reflects the problem I had in the second instance, rifle would chamber factory ammo fine and fire, but on extraction (lifting bolt and pulling back) the bolt would lift easily, but be very difficult to actually pull back. It was clear what was happening, as the brass would show signs of stretching (get yourself a case gauge-where you drop the brass in).

Impossible to explain how else you are getting issues. If you follow my instructions this will more than likely show up as being the problem (your fired cases should also show signs of excess length, growing a lot lengthways during firing). I'd insist to the dealer that they fire a few shots themselves and see. The fuckwits who sold me the rifle with excess headspace told me their gunsmith reckoned that 'All Remingtons are like that'.

Thankfully I managed to replace the bolt with an original Remington one off a shot-out rifle.

Never ever used them again, complete idiots.

I think dealer is wrong. It's not going to be a resizing issue. If you can chamber the case freely then the die has done its job.

Try a different brand of brass. (Not Federal, GLF, or Norma) Your brass is too soft for the load.

I'm going to defend the dealer here because as far as dealers go, I and the people I know who buy there rate him. At this point he is doing his best to help sort this, including talking to the NZ Ruger importer this week for input.

His position is that the three lug design is common to more than one brand and is known as a design to be picky and a tad weak on extraction, sensitive to any brass sizing issue. He did something we should have done which was to mark the brass that would not eject. He returned the doz reloaded brass he fired with three marked. I had the rifle owner around yesterday and with the magazine in we individually chambered each piece of fired brass. The three marked pieces all entered the chamber freely and all locked the bolt up on extraction. When I say "locked up", the bolt would lift freely to what seemed like the top of the stroke but could not be drawn back to open. As in the field after firing, the bolt opened after several attempts. In the field we assumed that there was a heat issue and that the brass ejected after cooling some. Wrong. In the workshop I made these attempts really slow and deliberate and I noticed that on the final successful bolt lift the bolt perceptibly clicked and lifted infintismally higher and free. We repeated this to be sure. Somehow, the bolt was sticking at that final point. I don't really have a clear picture in my head of the detailed mechanical operation of the bolt internals at that point. But what we now had was repeatability with the same pieces of brass.

The dealer lent me a used set of Hornady New Dimension dies. Same as my own. Keeping the three marked brass separate I annealed all the case necks, full length resized and decapped them, and length trimmed them. Then we ran them back thru the rifle chamber. No extraction issue. So we reloaded them with the same 139gn Hornady SSTs and same batch of 2208 but following @grandpamac advice, dropped from 42.8gn to 42.0gn load.

Now to shoot them.

In running the 12 sized cases through the rifle on a different four cases we felt a minute tad more resistance chambering at bolt closure. Hard to be sure but we marked these cases to track them on firing.

The 12 cases are mixed headstamp, Winchester, Sako and PPU plus one oddball. Now I know that will get a reaction but this is standard hunting ammo out to 200m, not long distance or bench rest. Mixed headstamp brass is immaterial accuracy-wise for this purpose and these are very accurate in this rifle. The three problem cases are each a different headstamp.

The other thing I did differently this time was to change from my Lee Classic Cast press (hard stop) to my RCBS Summit press (cam over). All the cases were carefully hand lubed to resize including brushing the inside of the neck. The used loaner
Hornady dies I cleaned internally with Isopropyl alcohol before using. I broke the Summit. A couple of the cases were more resistant to withdrawing from the die, not stuck but heavy. The cam-over was set to be just firm/crisp but not heavy. The value of using camover, I reasoned, was a consistent degree of resizing pressure from the press for each case. On a hard-stop press, like the Lee it's possible to get tired, inattentive or lazy on the sizing stroke and not make the fullest possible down stroke. In essence this is what the dealer was suggesting was happening on the extraction issue - some brass not being completely resized. If all the brass exhibited the extraction issue one could blame an out of spec die, or rifle for that matter. With only some cases and different ones each time one has to suspect the integrity of the sizing operation. If only some of the cases and the same ones each time, the problem has to be the case. Right?

Anyway, I don't know when the top-casting on the Summit started to break but it came apart when we were near the end of seating the bullets so we had to finish that operation on the Lee. I will discuss the Summit issue as an update on my old thread that originally reviewed it rather than hijack this thread.

So finally, our next step is to fire the 12 reloads and see what happens. Will be another 10 days or so to get to that and then I'll post the results here.