While shooting today I had the bolt stick a little. The handle rotated freely, but when I tried to pull it back it stuck. I pulled harder and it came free. This was a factory load.

I have a couple hundred once fired cases of this same ammo. I next measured them, and found them to be three thousandths over trim length, and well under listed max length.


Bullet will not drop through once fired case. Loaded factory ammo neck = .305
once fired neck = .308
resized neck = .302

If this was one case out of a couple hundred fired in the same chamber, I wouldn't lose much sleep over it, unless the anomoly was repeated. Sometimes if a chamber gets heated up a case will stick. Sometimes the one case may have a little thicker neck wall than the others. Did you measue the base web for unusual expansion? With the bolt handle lifting easily, did you see any fresh scarfing of the case base head to indicate the case remaining stationary in the chamber while the bolt was turned? How did the primer look as compared to all the others?

I actually felt a little stick on three or four of twenty. This one stuck hard.

Barrel did not get hot.
No scarfing I can see.
Primer looks the same.
Expansion is the same as others.
Case length is the same.

Only difference I can see is the case mouth is bent, like it buckled in.

It was quite cold. 15 degrees. Maybe the case mouth buckled due to the extreme temp change? Caused out of round and a pinch?

Only difference I can see is the case mouth is bent, like it buckled in.


Wht rifle and what caliber?

That buckeled in comment caught my eye. IF it isn't being dented in by htting something in the ejction process, then you might have a problem.

270 win. Model 70 stainless sporter pre 64 action.

Don't know where it happened. I've seen dented mouths before. I've always attributed them to extraction.

I do know it seemed to me the case neck was stuck. I can see a faint impression of the chamber on the neck of fired cases. This impression is more defined on the case that stuck.

270 win. Model 70 stainless sporter pre 64 action.

Don't know where it happened. I've seen dented mouths before. I've always attributed them to extraction.

I do know it seemed to me the case neck was stuck. I can see a faint impression of the chamber on the neck of fired cases. This impression is more defined on the case that stuck.


Factory loads?

Would first clean the rifle's chamber. A bit of baked on filth or hardened oil would do the trick, taking up a bit of room at the case neck so the case couldn't expand fully (raising pressure) and providing a rough surface for extraction.

As this area is larer than bore size..and many people use a bore guide that covers the chamber up...they tend to never get really cleaned.

Factory loads.

Thanks. I'll clean it thoroughly. Seems the most likely explanation.

Are the necks thicker on the cases that stuck, vs. those that did not?

It would be nice if you had access to a bore scope and could get a really good look at the chamber. If you can get one, look for build-up where the chamber neck area steps down to the start of the freebore. Have you been shooting any moly-coated bullets through this gun? They especially tend to cause build-up there.

The other thing you mentioned is that a bullet won't drop through your case neck. This may or may not mean anything. It is usual that the last 10-20 mils of a case neck don't expand as much as the rest of the neck, and sometimes the bullet will not pass freely through that last little bit, even though the rest of the neck opened up just fine. In my .308's and .223's, the mouth of the neck is 0.002"-.004" narrower at the end than .02” behind it.

This happens because the neck expands from the breech end forward under pressure. Just as the last couple hundredths expand enough to let go of the bullet, gas starts to escape. This equalizes the pressure on the outside of the incompletely expanded end of the neck, so it has no pressure differential to finish expanding it.

The thing you want to know is whether the case behind the case mouth is opening up as it should? If not, you either have a tight or dirty chamber neck. In the latter case I would consider plugging the breech and funneling the chamber and barrel full of carburetor cleaner or Slip 2000's carbon remover. Let it sit a few hours to soften the carbon. After pouring the cleaner back in its can and using a couple of dry patches, spin a bronze brush in the chamber neck and see what comes loose?

If nothing comes out in the wash, consider having a gunsmith touch the inside of the chamber with a chamber reamer. Caked-on carbon or tight neck dimensions would both be cleaned up by this.

Nick

Hello Nick,

No moly's.
No borescope. I'll ask around though.

Light use of a deburring tool allowed the bullets to drop in, confirming your suggestion.

Neck walls are consistent.

I'll clean 'er up. I've always kept this gun well cleaned. Prior to the days shooting, I cleaned it in the evening. Let it soak over night, and finished in the morning. I use Tetra gun copper solvent. I've noticed on a handgun, the carbon can be stubborn. Is there something more effective for carbon, (carbuerator cleaner?) I should be using in my regular cleanings?

Is it possible my choice of solvent is allowing carbon build up? I would expect the neck and throat to be cleaned along with the bore. Do they require seperate attention? How do you clean them (aside from already mentioned soak)?

Grit,

This place makes two products. Carbon Killer is for general gun carbon removal, and Gas Piston Parts and Choke Tube Cleaner, which is their super strong stuff:

http://www.slip2000.com/

For military calibers you can get chamber brushes. These have wider bristles at the stern for the case body area than the neck area of a chamber. Hoppe's sells a chamber cleaning brush that is a short cleaning rod made of flexible plastic to go around a corner and into a chamber, including through the ejection port if necessary. Brownells sells these as their part #699-201-003 for '06 size cases. Brownells also has a separate line of chamber brushes of their own that would fit the same handle. The handle is fixed to the shaft, so you push the brush in and rotate it by hand to clean.

In your case, the neck being the only concern, you could put a .30 cal brush on a rod, push it into the neck and turn it a half-dozen times. Continue to turn it while your are pulling it out of the chamber so you don't reverse-kink the bristles. If you want to take a go at the rest of the chamber, try a shotgun brush.

After brushing, point the muzzle down and blow a little Bore Scrubber or other solvent down to rinse out the chamber.

Nick

Get alot of neck build up with some ammo...exp. the military stuff that uses some kind of asphalt like sealant but other types do it as well. Bore guide hides that part.

Can get a build up seriouse enough to make extraction a problem.

The sealant just laughs at some solvents.

The ammo is Remington Kore Lokt.

I'll get her cleaned. I think this is the problem. I appreciate the help. It sure is nice to have resources like this forum. Thanks for the link.

Happy Hunting.

. . . the military stuff that uses some kind of asphalt like sealant. . . The sealant just laughs at some solvents.

That black stuff is pitch. You can theoretically melt it out. Amateur astronomers melt and cast it to make mirror laps. At chamber temperatures it should be at least partially carbonizing, so I expect the carbon cleaner would get it. If it not carbonized, an overnight soak in naphthalene should loosen it. Patches wet with MEK should also dissolve it, but watch the fumes and the stock finish.

Funny thing is, match shooters noticed long ago that military match ammo out shot commercial match ammo loaded with the same components. I think it was noticed in .45 pistol first, since commercial rifle loads didn't use FMJ boattails, but rather the superior commercial hollow point match bullets. Until M852, that is. It was finally demonstrated that the credit went to the pitch. It was adding just enough adhesion to make the start pressures higher and more uniform. I believe this is what inspired Lee to come up with their factory crimp rifle dies? They are another way to increase start pressure and make it more uniform.

Nick

Carb-cleaner fluid and a one-size-larger brush seems to do the trick nicely.

Do remember pitch...did actually grind a 8" reflector when i was a kid, and other than some color distortion, made a fine scope. Also lined the disection pans in Biology and Anatomy 101.

Remember attempting to inertia pull some S&W factory loads, the little 90gr. JSP .38specail laods they once amde with a kind of hemisperical shape. Managed to inertia the lead core out of the jacket, leaving the jacket firmly in teh case mouth. Once I pliers-mangled the jacket out, found not ony a very ehavy crimp, but a bit of asphalt sealant.

They must have found the 90 grain too light to get the powder to burn well. I didn't know anyone had used this trick commercially? The military just wanted to waterproof their rounds.

Achromatic lenses used to be expensive, and I don't think Edmund even sells mirror grinding kits anymore. Modern tech. Bah, humbug.

Nick

They must have found the 90 grain too light to get the powder to burn well. I didn't know anyone had used this trick commercially? The military just wanted to waterproof their rounds.

Achromatic lenses used to be expensive, and I don't think Edmund even sells mirror grinding kits anymore. Modern tech. Bah, humbug.

Nick

This is getting far from cse neck problems, but i'll get around to that.

Forget now where I ordered the blanks...do know I had a 1959 hardbound collection from Scientific American aimed at teens. Not only a refelctor, but had plans to build a simple x-ray machine as well (Yep...it worked), smograph, etc. All in all, some of the stuff they had in that book proably shouldn't be done today.

Back to the problem at hand.

Would measure that chamber's neck leght just to be sure it isn't a bit short. IF it were, and a case a bit long used, would have a problem with bullet release...pressure increase...and a problem extracting.

Not common...most chambers are "generous" in their neck length, but every so foten will find one just a bit short.

This is getting far from cse neck problems, but i'll get around to that.

Me too.


Forget now where I ordered the blanks...do know I had a 1959 hardbound collection from Scientific American aimed at teens. Not only a refelctor, but had plans to build a simple x-ray machine as well (Yep...it worked), smograph, etc. All in all, some of the stuff they had in that book proably shouldn't be done today.

If you still have that book hidden in a chest somewhere, I'd sure love to see a scan of or even just know the title so I can try to find a used one. I love that stuff and have a number of pre-war amateur scientific and project books. It would probably be fun to scan and PDF it. Scientific American lawyers would have a heart attack, worrying over the liability that kind of information brings.

I subscribed to the Scientific American all during high school (60's for me) and the Amateur Scientist was my favorite department. I even got C.L. Stong's glass blowing book and my first issue of Popular Electronics because it had a high voltage supply project, and I needed both to build a helium-neon laser Stong described in that column. Starting college as a chemistry major, I was the only person there who could do any glass blowing. They had a nice glass bench going unused. But I changed majors because the electronics bug that bit me on that laser power supply project took over and wound up becoming most of my career.

I also picked up a 1932 amateur telescope building book a decade or so back. You would not believe how dangerous it was to silver a mirror on your own. I had a physics prof. in college who'd had a silvering tank blow up in front of him. Accidental formation of fulminate of silver in the reduction solution was common. He said all he remembers is suddenly the room and tank shrank very small, like the image on an all-vacuum tube television did when you turned it off. Next thing, he woke up under the emergency shower, where a couple of fellow grad students had dragged him to wash the acid off.


Back to the problem at hand. . .

If cleaning doesn't solve Grit's problem, we need to talk him into buying a bar of Cerrosafe. A chamber cast is the best way to make sure someone didn't chamber his gun with a worn and over-sharpened or a custom reamer. Alternately, you can cast a pure lead bullet, preferably a long bore riding design, and stick a dowel into a fired case that comes up just past the shoulder. Drop the bullet into the case, wipe it with a patch sprayed with Pam and chamber this assembly. You may need to pull the bolt and use a dowel and hammer tap it into battery. Then take a brass or CRS rod and a heavy hammer (2 lb or more works best, so the inertial swing does the work) and leaving the action loose on a table on a carpet remnant or other soft pad, hold the muzzle with your weak hand and tap the rod until you feel a resistance increase. You can hear a change, too. This is from the lead having swaged out into a slug and become a firmer obstacle.

With a bit of practice, you can tell when you’re done. This slug fills the space ahead of the case neck, and after extracting the case, you very gently tap the slug out and have a lovely and accurate impression of the space ahead of the neck and of your throat. Veral Smith makes special lead rods for this purpose for those who don’t have a mold. $4.00 if I recall correctly?

Nick

Nick:

None of the books survived Katrina...not sruprising as not much of anything else did either, but that particular book was given to Delgado Community Colledge's radiology program...has a favored teacher that appreciated that kind of thing (X-ray machine...no doubt he's tried it by now, but vacuume tubes and neon step-up's equally hard). Pretty simple...just liek the originals...would take about 4 min. to get a decent x-ray (while today's machines will take a few 1/100's seconds).

I'll measure chamber length with a lahed turned "button"...one end a nice push fit into a case neck, the other end the diameter of the OUTSIDE of the case. Can sit there on teh lther and play with the steel "button" but it's easier to just keep trimming the case enck until it just barely fits. this will give you the real measure of the chamber...and give you teh real length that is a "must trim max.".

Sure you could file one out on a spinning drill...and get just as good a measurement.

Ribbonstone:

I didn't realize you were from New Orleans (I don't often look at the profiles). Sorry for what you've had to go through down there. I have a friend from Port Arthrur who sustained a lot of damage to his home and business. His blind sister now lives with him because her house in Slidell was literally flattened. Doesn't look like the political wrangling will end any time soon, either, even if the game of pass-the-blame has stopped making headlines.

On the chamber neck. Do you own a set of small hole gauges? Those and a micrometer will tell you what you want to know without making a tool. The lead has the advantage of showing the throat, freebore length and all that, but if the neck is all you want to know, the gauges are great. I use mine all the time and can usually get within about 1/5 of a mil with them. Close enough to determine a pin press-fit, anyway.

A set to go from 1/8" to 1/2" is $30 in Chinese knock-off variety. Considering most chamber reamers taper the neck down a couple mils from the shoulder end, this should be pretty easy to measure with one. If your fingers can't adjust the gauge in place, use the micrometer to set a diameter, then adjust the gauge to just kiss the anvils. See if it falls in? Run it a couple thousandths at a time until it stops about half way down the neck. That'll be the average.

http://www.use-enco.com/CGI/INSRIT?PMAKA=615-6250&PMPXNO=949268&PARTPG=INLMK3

Last four mounts have taught me to make do with what i have...did have pin gauges, but would do it the primitive way if i had to do it today. For taht matter, for just one reading, would be tempted to use eaiser to machine/file materials like brass or Al.

Yep..is a Harbor Freight outlet not too far away....not alergic to cheap China-made tooling for most things. Even today, 4 months after the storm, are times when you'd better grese yourself to slip into that store; are doing a big bussiness in construction tools.


Suspect the original poster's problems will evaporate after a good cleaning...come to think about it, hard to think of any gun problem whose solution doesn't start with a good cleaning.

. . . or which doesn't clean up with a good solution!

Nick

Sorry. Can't resist a dumb pun.