Over-pressure? Couldn't extract case, Marlin lever won't lock anymore

G

Gawp

New member
Hi,

Today I tested a new load:
* Caliber: .30-30 Win
* Bullet: Hornady .308 170 gr (#3060)
* Powder: 0.570 gram of Vihtavuori N32C
* Primer: CCI LR Primer

Additional info:
* I had no problem with 0.560 gram of Vihtavuori N32C
* I'm sure of the load because I weight each of my cartridges before and after I drop the charge into the case
* Some of the cartridges were loaded with 0.575 gram instead of 0.570 gram due to the precision of my powder measure (Lee Auto-Drum powder measure)
* I didn't measure the speed with a chronograph for this bullet but it was subsonic, there was no supersonic crack
* I shot it in my Marlin 336 XLR

So, I shot the cartridge and then I couldn't extract it. The extractor/bolt would open fine but the cartridge was stuck inside the chamber. I had to pull it a little with a thin knife blade (took care not to mess up with the gun itself), then tried again to close the bolt and the extractor finally extracted it.

The case has a deformed mouth (it's not a regular circle anymore) and on the body of the case there are many very little dots/holes, like they were "engraved" into the brass.

Plus, now, with some cases (not all), my Marlin lever won't lock anymore when there is a case in the chamber (and won't extract it either), even if it's a brand new/non-fired cartridge.

This locking problem/hard extraction problem also happened when the gun was brand new with manufactured cartridges and before I shoot any of my hand loaded ammo. Since the gun was brand new and the ammo brand I was shooting was quite popular/not cheap I thought it was normal. Note the extractor never failed to extract a cartridge before, even if it was sometimes hard (again, with the manufactured ammo).

So I got two questions:
* Is it likely there was an over pressure?
* What can be so wrong that now my lever won't lock and the extractor won't work literally half of the time?

Thanks for the help!
 
To save others from doing the conversion:

.560 grams = 8.6421 grains (rounds to 8.6)
.570 grams = 8.7964 grains (rounds to 8.8)
.575 grams = 8.8736 grains (rounds to 8.9)

My Lyman's 50th Edition doesn't have data for that powder, so I have no basis on which to comment.

Out of curiosity, where did you get your load data? The Vihtavuori web site doesn't show that powder for use in the .30-30 cartridge:

https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=29
 
Out of curiosity, where did you get your load data? The Vihtavuori web site doesn't show that powder for use in the .30-30 cartridge:
Click to expand...
I worked the load by myself to have a subsonic .30-30: https://thefiringline.com/forums/showthread.php?t=607053

I confirm the case expanded, because I can't chamber the empty case easily into the chamber, while I can with other non-fired empty cases.

The extractor works when I push it against the cartridge while lowering the lever but... not very practical.

For the lever not locking, it's actually all fine, it was because the cartridge I tried to chamber had a primer not seated deep enough.

So now the only problem is the extractor not working well anymore.
 
Since we now know that your reloads caused one problem, have you fully function tested the rifle with factory ammo?
 
The lever not locking/hard ejection also happened with factory ammo, yes.

And when I think about it, I'm wondering if the hard ejection problem doesn't happen specifically when the lever doesn't correctly lock?

When the lever doesn't correctly lock, the bolt is perhaps not completely in position, allowing the cartridge to move slightly when it is fired, and causing the case to expand?

Does it make any sense to you?
 
Anything is possible, but you are in uncharted territory.

According to the Vihtavuori web site, that powder is named "Tin Star" and it is intended for reloading old, low-pressure handgun rounds that originated in black powder days. It is a high bulk powder ... more or less, I suppose, like Trail Boss. The page on the Vihtavuori site that discusses N32C lists several cartridges that they consider this powder to be appropriate for. .30-30 Winchester is not one of them.

You have given us conflicting statements. First you posted this (in post #3):

For the lever not locking, it's actually all fine, it was because the cartridge I tried to chamber had a primer not seated deep enough.
Click to expand...

Then, in post #5, you said this:

The lever not locking/hard ejection also happened with factory ammo, yes.

And when I think about it, I'm wondering if the hard ejection problem doesn't happen specifically when the lever doesn't correctly lock?
Click to expand...
So the failure of the lever (and bolt) to lock is NOT just due to one cartridge with a high primer. How old is the rifle, and how many rounds have been fired through it (approximately)? Did you buy it new, or did you buy it used? Do you know if it has previously seen much use with "heavy" rounds? It is possible that the firearm had mechanical issues before you fired these rounds through it. It is also possible that firing these rounds may have made any pre-existing problem worse.

Is it possible for you to take the rifle to a qualified gunsmith to be inspected and have proper operation restored?
 
The Marlin has a two piece firing pin, which is designed so that it won't fire if the lever is not completely closed in the up position. When the lever is fully closed, it pushes the two piece firing pin into position and that allows the rifle to fire. So you should not have been able to fire the Marlin without the lever completely closed.

Check if there is something caught between the extractor and the side of the bolt that is preventing the extractor from fully engaging the cartridge rim.
 
|...] more or less, I suppose, like Trail Boss. The page on the Vihtavuori site that discusses N32C lists several cartridges that they consider this powder to be appropriate for. .30-30 Winchester is not one of them.
Click to expand...
Yes, because here in France I can't get TrailBoss, so the goal was to use N32C as a replacement.

You have given us conflicting statements. First you posted this (in post #3):
Click to expand...
This is true, I had the problem several times with factory ammo, but I also reproduced the problem with a hanloaded ammo which had its primer seated not deep enough (actually it was an empty case with only a primer that I randomly tried to see if it would extract). Then I seated the primer deeper, and it worked: I could lock the lever without any problem.

So the failure of the lever (and bolt) to lock is NOT just due to one cartridge with a high primer.
Click to expand...
I agree.

How old is the rifle, and how many rounds have been fired through it (approximately)? Did you buy it new, or did you buy it used?
Click to expand...
I bought it as new from my local gunshop a month ago. However it is probably way older than this because it's been imported from the US so... I fired about 75 rounds with it. All factory subsonic ammo, and:
* 5 handloaded rounds with 0.42 gram of N32C (avg 225 m/s)
* 5 handloaded rounds with 0.51 gram of N32C (avg 269 m/s)
* 5 hanldoaded rounds with 0.56 gram of N32C (avg 310 m/s)
* 1 hanloaded round with 0.57 gram (possibly 0.575 gram) of N32C (didn't use the chronograph for this one, but it wasn't supersonic)

So you should not have been able to fire the Marlin without the lever completely closed.
Click to expand...
I just tried it with an empty case, and indeed it won't fire. So it was probably closed correctly when I fired my handloaded ammo.

Check if there is something caught between the extractor and the side of the bolt that is preventing the extractor from fully engaging the cartridge rim.
Click to expand...
I can't see anything. Actually the extractor sometimes works. And when it doesn't, it works if I push on it with a finger so it grabs the case correctly.
 
Hmm.. let's calm down and look at the problems one at a time.

The rifle seems to have locking and extraction problem when it was brand new and with factory ammo. It may have short chamber and extractor fitment issue. Level actions requires a little more headspace in order to function correctly. You may need to send the rifle to the manufacturer or a gunsmith to check it out.

With this intrinsic issues of the rifle, it wouldn't be too surprising to have similar issue with the handload.

What's surprising is the little indentation marks on the brass. It would help if you can post a picture of it. I guess there was unburnt powder granules between the chamber and brass when you fired the gun. Where did the unburnt powder come from? Super light load could be a possibility. But more likely is you accidentally dumped it into the chamber when you extracted an unfired round with bullet seated too high. Those powder granules can get into places they don't belong and keep the action from closing. You will need clean out the gun thoroughly.

Let's us know how it goes? It doesn't seem to be over-pressure based on your descriptions though.

-TL

Sent from my SM-N960U using Tapatalk
 
Thanks for the reply tangolima!

I will have the gun checked ASAP then.

Here is a picture of the marks on the brass. Is it normal the case expanded to the point I have to push quite hard to chamber it (I tried to chamber it when it was empty, but had to push pretty hard)?

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looks like dots from tumbling media i have gotten when i resized and had some in the die. could be dirt, unburnt powder, or carbon buildup in the chamber. i would try and clean the chamber, its an easy place to start.
 
looks like dots from tumbling media i have gotten when i resized and had some in the die. could be dirt, unburnt powder, or carbon buildup in the chamber. i would try and clean the chamber, its an easy place to start.
Click to expand...
I use stainless steel media (wet tumbler) so it's probably not this but it might be any of the other things you said.

Have you considered entering your load data in Gordon's Reloading Tool to check the pressure?
Click to expand...
I did, and also in QuickLOAD. Both programs show the pressure would be about 1700 bar (= 24,656 psi) or in worst case about 2250 bar (= 32,633 psi) if the bullet was completely stuck/wouldn't move at all. So still well below the CIP maximum which is 3200 bar (= 46,412 psi).
 
Gawp said:
Thanks for the reply tangolima!

I will have the gun checked ASAP then.

Here is a picture of the marks on the brass. Is it normal the case expanded to the point I have to push quite hard to chamber it (I tried to chamber it when it was empty, but had to push pretty hard)?
Click to expand...

I haven't seen N32C powder myself. Do those dots match the powder granules? If you have those in the chamber, you will have hard chambering, or simply can't close the chamber at all. Also when you tried chambering, were you using a fired brass or a resized one?

When I come to think about it, you had speeds way below the simulation results when you loaded with 0.5 gram, did you not? That load could be so light that there were unburnt granules left in the chamber. The low speeds were caused by incomplete combustion.

-TL

PS. Found picture of N32C. It does look like the indentations. https://www.vihtavuori.com/powder/n32c-tin-star/


Sent from my SM-N960U using Tapatalk
 
Carefully clean and wipe the chamber and the action, looking for any grit, dirt, unburned, partially burned powder or anything else that doesn't belong.

With a clean chamber test a factory round and see if the rifle behaves differently.

The "dots" in the case are the result of something being between the brass and the steel of the chamber when you fired it.

Once clean, things should work normally. If so, you need to figure out what got in there, and how, so it doesn't happen again.

One thing you need to make sure of is that there's no grit in there, AND that the steel of the chamber hasn't been marred. If the chamber has been scratched or otherwise damaged, you need professional help.
 
Unless I missed it, I don't think you have actually stated what the firearm is. Are we talking about a Marlin 36 / 336?

The fact that since it was new you have occasionally had to manually press in on the extractor to force it to engage the case head suggests that there was something wrong with the firearm from the beginning. Have you manually manipulated the extractor (with the firearm unloaded) through its entire range of travel to feel for grit or sticky spots in the movement? (What we might call in English "hitches.")

It might be that what's called for is a disassembly and polishing of the bolt and extractor surfaces.
 
I've had cases that were difficult to extract--because they weren't headspacing correctly--with only one or two pieces of material adhered to the chamber wall--you have what looks like a whole gravel pit in your's! ;) When you say your lever wouldn't close--do you mean it reached a certain position and you couldn't go any further--or did the lever just "pop" back open after closing it?
 
Your chamber is full of unburned powder granules that have been compressed and 'glued' to the walls of the chamber.
Scrub it out.

Your problems will go away.
 
You're only talking 12-13,000 psi w/ that (Quick)load.
As 44-AMP & Frankrnmauser observe, your chamber is a gravel pit.
Scrub/polish/Flitz the bejeezus out of it and get those chamber walls looking like mirrors.
 
Sorry I've been busy and didn't see this sooner. FrankenMauser is most likely correct. Because this is a very low pressure load, the case mouth is not expanding to seal the chamber completely. This allows pressure to blow some granules of the powder back between the case and the chamber. I've seen the same thing happen with very light target loads in other guns.

Use a good powder solvent and a chamber brush to clean the chamber out and the problem should clear up. I would take the gun down and check for the granules in the action as well.
 
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