Difficult Extraction...

[Tom68]

Yesterday I had an issue with extracting fired cases. The bolt lift felt normal, but after the lugs cleared the recesses, the bolt handle was extremely difficult to pull to the rear. In this case, I do not think overpressure was the root cause, and wanted to hear some suggestions here that I may have not considered.

I don't have all my data here with me right now, but I'm using a new Savage Model 10. The basics as I recall follow:

.308 Winchester
Federal Brass, FL resized
168gr SMK
CCI 200
IMR 4064, and RL-15, starting at 2 grains below max and 0.5 gr intervals
OAL: can't recall, written in my notebook but not on me at present. (seems it was right about Speer #14 test load... not overlength for sure)

The sticky extraction problems existed in many rounds, from those at 2 grains below max all through max load, and none showed ejector marks or flattened primers. as stated before, bolt lift was not a problem. The only previous time I fired this rifle was with factory ammo, and an initial handload of Varget (same formula as before, 2gr below max in 0.5 intervals, same 168 gr SMK).

What I did NOT do is to set the lockring on the FL die: I set it by "feel" both times, with a slight cam-over, and I tested a sized case in the chamber (with no difficulty chambering or extracting) before proceeding with the entire batch. I do not have a chamber gauge, but in loading for 9 other bolt guns I have never felt terribly underequpped (although I do recognize I could be more precise with one).

For what it's worth, some of the loads showed some really trememdous potential, well under 0.5" at 100 yards. I expect even better when I get around to trying other primers and especially higher quality brass.

So, since I do not suspect overpressure as the culprit, I'm wondering if the shoulder was not set back enough for this particular rifle (even though it chambered effortlessly), or if maybe I failed to remove all of the case lube off the cases, or even left some oil in the chamber. I'll thoroughly clean the rifle this evening, and will be more diligent to ensure the cases are free of lube before using... but in the meantime, I'm interested to see if the community has any other suggestions I may have not thought of?

[GeauxTide]

The case head to see the expansion. Factory is .470. If your case measures greater than .4705, your load is above safe working maximum. Just for giggles, I'd check the length. Max is 2.035", with trim length of 2.015".

[condor bravo]

Examine some of the difficult to extract cases that have not yet been resized and look for possible projections (opposite of indentations) on the case walls. If so, report back and I will continue. If no projections, disregard.

[T. O'Heir]

"...it chambered effortlessly..." Eliminates a lot of culprits. Any chance the safety was partly engaged?
OAL wouldn't apply to fired cases. The actual load used might though.
Not setting the lock ring on the FL die means it may have moved. Wouldn't matter after the shot either though.
Max for .308 is 2.015". Trim-to is 2.005". Max OAL is 2.800".

[Tom68]

Thanks for the replies so far.

I'll check the case head expansion tonight: will compare the fired cases with unfired, sized cases from that same batch. My calipers only measure to the nearest 0.0005" so it may not be precise enough to determine a problem. I'll see.

Definitely will look for protrusions on the sized cases: don't think that will be it, though...I may not use a magnifying glass, but I do inspect each cartridge that I load.

safety definitely was not partially engaged. rifle has a three-position safety, so it would have to be "two-thirds" engaged in order to lock the bolt--and the bolt handle operated freely. it definitely was the case stuck in the chamber.

so far I'm thinking that I must have not cleaned the cases well after sizing. or maybe it was a pressure problem after all, and changing brand of cases may help. Perhaps I can compare case volume among brands and see if that may be it. Maybe someone will come along with some more suggestions.

[condor bravo]

Look for projections on the case walls after they have been extracted with difficulty but not yet resized rather than "on the sized cases" per your reply. If the fired cases have been resized, the case walls will be ironed out and we would probably miss what might be the culprit behind the extraction problem. If projections exist, there is definitely a problem that can be pinpointed.

Note that these projections, if there are any, will not appear over the entire case, but probably just within a confined area, like within a half square inch or maybe a little larger. If the presence of projections can be eliminated, then perhaps over pressure may have some validity but I am not yet convinced of that.

[steve4102]

Check your OAL against the distance to the lands.

Savage is putting out some short throated 308 Rifles where even factory ammo is getting stuck in the lands.

If your load is jammed into the lands you are going to experience a higher/over pressure situation.

[WVMountaineer]

Sounds like pressure to me. God Bless

[Tom68]

Okay, here's the raw data I couldn't provide earlier:

All cases were trimmed to 2.005"
OAL for each load was 2.795" (max per Speer is 2.810")

cases measured just above extraction groove:
"Cool" loads for fouling: .4691" avg (7 measured)
"Sticky" cases causing extraction problems: .4698 (12 measured)
Hi: .4705 (2 of 12)
Lo: .4690 (1 of 12)
Un fired sized cases:
Winchester: .4689 avg (6 measured)
Hdy Match: .4695 (6 measured, SD=0)

Here are the results of load testing:
Factory ammo (Hdy match, and Creedmoor): no extraction issues, ~1" @ 100 yds (wish I had measured OAL, could have been useful)
Fodder for fouling: BL-(C)2, 41gr, WLRM primer, 147gr FMJ, OAL= 2.758", no extraction issues, about 2" @ 100yds
Varget, 44.5, 45.0, 45.5, and 46.0: 45.5 and 46 sticky bolt lift but no extraction issues. Best group 44.5 = 0.359@100 yds. OAL = 2.795
IMR 4064, 44.4, 44.9, 45.4, and 45.9: no sticky bolt but extraction problems throughout. 44.9 = 0.670" @ 100 yds. OAL = 2.795"
RL-15: 43.5, 44.0, 44.5, and 45.0: same situation as IMR 4064. Best group 44.5 = 0.487" @ 100yds

Steve may be onto something I hadn't considered: short throat. All my test rounds were at the edge of max OAL so that could be it. Even though the case head measurements don't scream over pressure, obviously something isn't right so I probably ought to seat them deeper next go-around. I don't readily have the means to measure distance off the lands though... Maybe I can borrow a Dremel and cut a case to do so.

Either way, this rifle has some great potential, but it's a first for me in having to limit OAL to several hundredths under max.

So, given the additional raw data provided, what does the group think?

[condor bravo]

Since the extraction problem is not happening across the board with all ammunition, disregard my previous postings. Especially so if the rifle is new or near new. The problem displays the classic symptoms of a more serious problem that you don't want to have. Preferably the problem will be something else like high pressure that is easily correctable. But check back in should what I have been calling projections appear on the fired cases.

[Jim243]

The only time I ever had "hard case extraction problems" was with over pressure loads. The cases were not over loaded or above max loads, but the OAL for a particular bullet profile did the same as setting the bullet into the lands and causing the over pressure.

Since the hard extraction is not happening with the Hornady bullets but the Winchester ones, this may be what is happening.

This can be avoided by using a L-N-L Case length gauge and finding the Max OAL for a particular bullet instead of just taking the printed reference.

Just a guess.
Jim

[Mobuck]

If you experienced "sticky bolt lift" with a certain charge and then continued to fire "up the ladder" loads, I'm concerned.
To check if you're jamming the bullet into the lands, simply load and extract the loaded round. You should be able to see the marks left by the rifling if it's too long.
I've shot lots of rounds that contacted the rifling (LOADED WITH THIS FACTORED IN). The only problem was you can't unload-many of mine would leave the bullet stuck in the lands.

[F. Guffey]

So, since I do not suspect overpressure as the culprit, I'm wondering if the shoulder was not set back enough for this particular rifle (even though it chambered effortlessly), or if maybe I failed to remove all of the case lube off the cases, or even left some oil in the chamber

Lubing the case will aid in extraction. There are reloader/shooters that lube cases for slide and glide case forming, I believe leaving lube on the case is a bad habit.

F. Guffey

[F. Guffey]

Then there is that other thing. The bolt can be raised with no effort. I would suggest you determine how much the bolt cams back when the bolt is lifted.

F. Guffey

[James K]

I suggest cleaning the chamber thoroughly. I would not lubricate the cases, as that can increase bolt setback; in fact, make sure sizing lube is removed from the cases.

Also, are you annealing your cases? If so, tell us what exactly you are doing.

Jim

[Tom68]

James, I am not annealing cases. The ones in question were on their second firing. Chamber has been thoroughly cleaned, and I will ensure the case lube is completely removed before putting them into the chamber, even though I now believe the problem is pressure due to seating the bullets too long. Jim243, i agree with you... so that is the next change I intend to make in order to address the problem.

Mobuck, I hear you on the completing the ladder even with pressure signs. I did not complete the three-shot group for those two charge weights after experiencing a sticky bolt. As they were loaded to the same OAL as the later batch that had difficult extraction, I will try them again with a shorter OAL and see if that addresses the issue.

[Unclenick]

Tom,

Several potential issues:

Originally Posted by Tom68

IMR 4064, and RL-15, starting at 2 grains below max and 0.5 gr intervals…

…IMR 4064, 44.4, 44.9, 45.4, and 45.9: no sticky bolt but extraction problems throughout.

I've twice run into manual starting loads that were already at maximum for the rifle I was using it in. One was a .243 load from the Speer manual. Don't try to take a shortcut. Always start with the starting load, which should be 10% below maximum. It only takes 6 cartridges going from -10% starting load to maximum in steps of 2% of maximum. It's too easy and inexpensive to skip.

If your gun has a "fast" barrel or short throat, your pressures will be higher than the manual author got with the same loads. Manuals are a suggestion, but not a biblical edict.

Federal Gold Medal Match load fo the 168 grain SMK is 43.5 grains of 4064 using a Federal 210M primer. I would certainly be starting below that load so as not to miss it as a possible accuracy load. I would be below it especially since you are using a different primer, and even though your Winchester cases, in some lots, have a couple of grains more water capacity than Federal cases do.

Originally Posted by Tom68

OAL for each load was 2.795" (max per Speer is 2.810")

You are not shooting a Speer bullet. The ogive radius of the SMK may be different from Speer's. Sierra and Nosler 168's have close ogive radii, but the Hornady 168 has a longer one. I don't know where Speer's is. They could be a different distance from the throat for the same COL, therefore.

The 2.810" number is the SAAMI max, and is a not-exceed only for the purpose of ensuring your cartridges will fit in all magazines made to accommodated the SAAMI standard number, and is not about fit into a chamber. SAAMI has no clue what your particular bullet's ogive radius will be, so you have to check its fit in your gun. In general, if you are loading a bullet in contact with the lands, pressure will be about 20% higher than when the bullet is 0.020" to 0.050" back of the lands (depending on the shape of the ogive). The .308 Win standard chamber is different from the ball throat chamber in the .30-06, but if your freebore is short, you might need something a little shorter than standard. Sierra normally gives the COL for the 168 grain SMK 2.800" for their testing purposes, but that assumes a freebore of at least 0.090" (see SAAMI drawing). But with the .30-06 Springfield there is no freebore, and as a result, even though the SAAMI maximum magazine fitting COL is 3.340" for that cartridge, Sierra recommends 3.3290" COL for the 168 grs SMK, or 0.050" shorter. So you might want to try as short as 2.750" if your gun's freebore is AWOL.

The best idea, though, is to measure what you have. Though not precise, to get some idea, take a ¼" wood dowel and put it down your barrel until it touches the face of the open bolt. Check that the ejector doesn't interfere, then close the bolt slowly with the muzzle up. Mark the dowel with a pencil flush with the muzzle or use a single-edge razor to mark it flush with the muzzle (more precise, but not necessary for a general idea). Open the bolt and drop a bullet (not a cartridge; just the bullet) into the chamber. Use your pinky finger to press the bullet base so the ogive of the bullet is against the throat. If this proves difficult, remove the bolt completely and use the eraser end of a pencil or some excess wood from your dowel to hold the bullet against the throat. Let the dowel in the muzzle rest on the tip of the bullet and mark it flush with the muzzle again.

The distance between the two marks on the dowel is the COL that will put that bullet in contact with the lands. You will probably want your actual COL at least 0.020" shorter than that, and preferably 0.050" shorter until you are satisfied your load level is not causing the problem.

Pressure signs: The reason sticky bolt lift occurs as one of the several pressure signs is that it happens when the case head surface flows into the gaps between the extractor and bolt face and the ejector tunnel. These latch the bolt face so there is resistance when you turn it. If the fit of your extractor and ejector are tight, or the head is not expanding, you may not get rotational resistance.

Case head expansion and pressure ring expansion really require an OD thimble micrometer to resolve accurately. They can be had for under $20. However, as board member Denton Bramwell shows in this article, no case pressure sign is calibrated and the same sign can appear on different members of the same lot of brass at measured pressure differences of almost 2:1. Bring different lots of brass, much less different chamberings, into the equation, and that spread gets worse. More recently, at the Shooter's Forum, two fellows using a pressure trace on several rifles have found the classic pressure signs on a modern case supported by a modern chamber aren't normally starting to show up until about 75,000 psi. All an indirect pressure sign, like those on a case or on a primer or the sticky bolt lift tell you for sure, is that you are exceeding the pressure limit for the components giving you the indication. Whether that exceeds the tolerance of any other component or not is up for grabs.

So, the bottom line is that you could be far enough above the pressure of the commercial loads you are using to start getting a symptom they don't produce, especially since you didn't start your load workup at a starting load and probably don't have an easy way to know how the water capacity your cases compares to that of the cases used to work up the original load data. Nor do you know exactly how your gun and chamber compare to theirs. The worst case scenario would be that you have a ringed chamber and that your loads are warm enough to leave brass protruding into the ring, while the commercial ones are not. To check for that, look for a shiny ring on your cases where they were scuffed during extraction. If you get such a ring, feel for it with a wire probe. Be aware that caked up fouling could do it too. Slip 2000 Carbon Killer may be needed to remove caking. Work your loads back up from a little further down and see if the actual starting loads don't make the problem go away.

[603Country]

I recently had a rifle rebarreled. It was chambered with a tight Match chamber and I had not asked for that and had not been informed of that. At slightly above starting loads I was getting serious pressure signs. The previous barrel, factory original, had allowed me to go to full max with that powder and bullet. It took me a while to finally understand what had happened with that new barrel, but I did figure it out and return the rifle to the smith. He opened up the chamber to standard dimensions and all is now well and it shoots like it should with no pressure problems.

I had several rifles rebarreled prior to that one, and never had any pressure issues that I'd have considered abnormal.

[Tom68]

Unclenick, I was hoping that you would chime in. I always enjoy reading your posts, as you provide a whole lot of relevant information that I almost always find useful. Roger on the starting at minimum and working up: after 6 years of this I had gotten away from that because my most accurate loads had never been at the bottom end of the range, but as you said, it is too easy, too inexpensive, but still wrong to go about things in that manner.

I don't start new threads too frequently, but I can say that I've learned more from this one than any of the others. If I make any big discoveries on my next range outing, I'll provide a follow-up.

[F. Guffey]

Then there is that other thing. The bolt can be raised with no effort. I would suggest you determine how much the bolt cams back when the bolt is lifted.

I will ask again, does your bolt move back when the handle is lifted, or put another way does your bolt cam back when the handles is raised.

When someone mentions 'stick bolt' I have no clue if the bolt is 'sticky' then the bolt handle is raised or if the bolt is sticky after the handle is raised.

F. Guffey

[ammo.crafter]

Can we assume the powder scale you are using is dead on accurate?

Under loaded rounds also increase pressure.

[F. Guffey]

Under loaded rounds also increase pressure.

Also increase or can increase. There is a point in there somewhere when the primer protrudes, meaning the case head did not seat against the bolt face because the pressure was too low. Then there is the that event that renders the gun scrap and no one can do every time.

F. Guffey

[Tom68]

Guffey, by "sticky bolt lift" I meant that it required more effort to lift the bolt handle than what I consider "normal". the first time it occurred was not substantial, but I did notice it... at the next charge weight it was more noticable (and I did not shoot any more of either weight after that). The bolt does cam back after the handle is raised.

Ammo, the scale is an RCBS 505 and the last time I checked it a few months ago it was right on. I'll borrow some check weights and check it again since you mentioned it, but I'm pretty sure it's still on.

[F. Guffey]

Yesterday I had an issue with extracting fired cases. The bolt lift felt normal, but after the lugs cleared the recesses, the bolt handle was extremely difficult to pull to the rear.

by "sticky bolt lift" I meant that it required more effort to lift the bolt handle than what I consider "normal".

I thought you said the bolt lift felt normal. Difficult to extract goes with a difficult to lift bolt handle.

F. Guffey

[F. Guffey]

but when the bolt cams back the case is extracted from the camber.

F. Guffey