Failure to trim?

[cloverleaf]

Thought I would pass this along. Pics of the cases below show cases now trimmed to 1.902. Prior to trimming thesse were at least 1.924. In the photos you can see what I can only guess is imprints of the rifling on these over length cases. They are not cracks If understand correctly, this could result in an over pressure situation. Note these cases have been reloaded many times. I wouldnt have seen this had I not taken some scotch bright to the shoulders/ neck. Others with more experience please comment. CL

 

[TackDriver284]

What cartridge is this? If your book trim to length is 1.902" and if the cases were 1.924", then I would say that the trim length is way too long unless you checked with a chamber length gauge to see what the max trim length is in your chamber. I would keep the trim length to no more than .005" over book trim length. Anything longer than .005" over book trim length, I would trim unless I use a chamber length gauge and measure my max trim length. Some folks do this and use a longer trim length to prevent carbon rings from forming on the throats.
Does those markings appear around the cases? Its possible the case necks are hitting something whilst chambering your rifle. Is it feeding smoothly?

 

[ElmerThud]

If book guide to trim is 1.902" I'd say MAX cartridge length should be 1.912".
As the mark only appears once on each case (unless I can't see properly)
it's possible? the marks are from striking the action while ejecting the case (It's a theory) rather than from the rifling..
In any event, 1.924" is as Tackdriver said, way too long.

 

[NYDAN]

It might be worth inspecting the neck and throat area of your chamber with a bore scope to see if there is anything in there causing those marks. Dan

 

[jimbires]

I'd say give the rifle a good cleaning , especially the chamber . it's possible you have a carbon build up , "carbon ring " in the chamber at the mouth of the brass case . I'd also give my die a good cleaning , maybe something stuck in there , or rust . I'm certain it's not marks from the rifling . the brass couldn't stretch enough to get to this length , also it would never chamber . ( see pic below )

I use case length gauges to measure my chamber length . I keep my brass cut to length for my chamber . most chambers are long , long enough you could be a little sloppy on keeping your brass trimmed to book spec and still be safe . but without a case length gauge you need to go by the published book length for safety .

I dug around and found a cut away picture of a chamber . you can see right at the case mouth a gap that allows carbon to build up . you can also see there is no way the brass case got into the rifling . I'm betting a dirty chamber , or dirty die is your problem .

https://www.armoryblog.com/firearms/rifles/barrel-chamber-cutaway-after-4000-rounds/

 

[cloverleaf]

Thanks all for the replies. 250-3000 Savage BTW. Of course you are correct, they were at least .010 over max length according to the book. Jim, good point, the Leede wouldn't leave the marks. I had a smith look at the chamber last spring, due to a couple separated cases, He said he "didnt see anything" wrong with the chamber, but I'm not sure how hard he looked.

Todays update has no photos because one of the cases in the photo (trimmed and spec'd out every way I could think of ) was loaded and fired. The action is now locked up tight and will not open. Will update if/when I get it to a smith and get the case out, I assume that somthing in my reloading process is some how out of wack. after all these years... ?!? I will be looking to find a guru locally to go over my loading process w/ me. I have the name and number of another smith as well. OR may just hang up the reloading endeavor altogether. CL

 

[wvbuckbuster]

CL it might be something you overlooked, or adjustment moved you hadn't noticed. The rifle locking up was in your favor that stopped something bad becoming worse. Get the rifle fixed, regroup and start over from the bottom and work up. Let us know what you find. Dan.

 

[RL338]

It might be worth inspecting the neck and throat area of your chamber with a bore scope to see if there is anything in there causing those marks. Dan

This ^

 

[Darkhorse]

Often while turning the case you can let it dwell too long and end up with a case either too long or too short. I kept records of my results until I got it figured out, then no more too long case lengths. It would be worth your while to do this.

 

[TXbaldhunter]

My rifles that I've checked with my borescope using a full length empty case show a generous amount of room for the case to grow beyond the max case length.I just make trimming every time a part of my case prep since I got my Frankford Arsenal Trim and Prep Center.I like to keep all my brass segregated by the same headstamp and number of times fired.Keeping everything consistent helps with accuracy,so why not do it.Here is a picture of an empty full length case in one of my rifles chambers.This is what I typically see in my rifles and you can see there is a lot of room for the case neck to grow.

 

[ShadeTree]

TXbldhunter, I often thought of that.........how long can a case actually be in a given chamber. I would suspect with most chambers there is quite a bit of room there off the end of the neck, but with no real measurements all you can really do is keep them within specs. I don't know that I ever read or heard anyone say for sure, but I would think you would want at least .020 clearance starting out prior to firing.

 

[TackDriver284]

TXbldhunter, I often thought of that.........how long can a case actually be in a given chamber. I would suspect with most chambers there is quite a bit of room there off the end of the neck, but with no real measurements all you can really do is keep them within specs. I don't know that I ever read or heard anyone say for sure, but I would think you would want at least .020 clearance starting out prior to firing.

This should help determine how much more you can safely trim.

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[ShadeTree]

This should help determine how much more you can safely trim.

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Neat deal. Cheap enough also. I was thinking a guy could make an attachment for on the end of the push rod in a Hornady comparator tool that would butt up against the neck cut out in the chamber. But for $6 it isn't worth messing with even thinking about it.

 

[NYDAN]

This should help determine how much more you can safely trim.

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Yes. These work well for determining how long your chamber neck is. I used one and was surprised by how much longer my brass neck could be. With my 300 Win. Mag. I could let the brass grow long enough to get a full bullet dia. neck length. Dan

 

[cloverleaf]

Thanks guys for keeping this going. Still working on getting the smith to open my rifle. (He's 100+ miles away and doesn't work weekends.) Also debating looking for a go/ no go gauge and just "horsing" the action open myself. I have long suspected that I have long leade. One firing will get me to max case lenght (according to the specs).

 

[NYDAN]

Cloverleaf, I was wondering how you are making out on this. Have you been able to get the action opened up yet?

I was also wondering how a gun smith goes about opening an action that is locked up. Does he/she unscrew the barrel? Dan

 

[Charlie-NY]

My rifles that I've checked with my borescope using a full length empty case show a generous amount of room for the case to grow beyond the max case length.I just make trimming every time a part of my case prep since I got my Frankford Arsenal Trim and Prep Center.I like to keep all my brass segregated by the same headstamp and number of times fired.Keeping everything consistent helps with accuracy,so why not do it.Here is a picture of an empty full length case in one of my rifles chambers.This is what I typically see in my rifles and you can see there is a lot of room for the case neck to grow.

This is the way to determine when to cut cases. Based on your image, I wouldn't cut that case until it was much longer. Taking steps to minimize the dreaded carbon rings is always a good idea.

 

[ShadeTree]

Cloverleaf, I was wondering how you are making out on this. Have you been able to get the action opened up yet?

I was also wondering how a gun smith goes about opening an action that is locked up. Does he/she unscrew the barrel? Dan

I'm not a gunsmith and I don't know how they do it, and I've never had to deal with a locked action, but if I was in CL's shoes I know how I would be doing it, or at least attempting it and seeing how it worked out.

Unless something is broken internally preventing the action from opening, a locked up action is a function of the brass being stuck tight to the chamber. I would take something like an old shotgun steel cleaning rod or something similar and come up with a blunt end for on it. Preferably no bigger than .20-.22 in diameter.

Carefully guide it into the exposed case neck and then to the bottom of the case. Using cloth and your hand to keep it centered in the muzzle, give it a good rap and try the bolt. If it doesn't work repeat a couple more times. All that case has to do is just move even .001 rearward and it's free where the bolt should function and be able to remove it from there.

If that wouldn't work I'd try putting the whole rifle in the freezer for a couple of hours. Cold contracts metal and my line of thinking is it would hit that thinner and more malleable brass quicker than the surrounding chamber. Don't know if that would work or not, but I'd try it if what else I tried didn't work.

 

[cloverleaf]

Shade, Charlie and Dan- Thanks for the inquiries, and the ideas. When I checked in with the guru at "The Gunstop" (Reloading Mecca in the mpls metro area) last week, he simply said, "you are over pressure- where are you on your ladder test?" Well, I wasnt doing that at all. Max load was 33 Gr in the Speer manual, I was loading at 32.5. Just picked it out of thin air. So, after much ruminating and some swallowing of my pride (some more) I pulled the bullet on one load and weighed the charge. With a "hammer puller" you can loose a little powder when the bullet lets go.
That load weighed 37 gr give or take a few tenths on two different scales. Same can be said for the rest of the rounds loaded when I pulled them.
So I figure, some how I got one "notch" down the beam. Even though I checked the setting multiple times during those 17 rounds, I missed it. Apparently Im having trouble reading the markings on the beam. Ive decided that I will need to get a digital scale to "double check my charge weights form now on. Any recommendations would be appreciated.
As for the rifle, I spoke with Dale at Little Crow Gun works- and he does have a Go /no Go gauge for a 250 Savage. I may just let him get it open, and then check the headspace. Unfortunately, that is 120 plus miles away from me. Time will tell. At least I didn't "eat the bolt". Look for another post about the usefulness of a digital scale. Do any of you have the gradiations on you beam scale highlighted some how? Might make it easier to read. CL

 

[Cleveland48]

Hope you get it sorted out CL, and glad it wasn’t worse! I use a rcbs light powder dispenser. Once when my little girl was big enough to ride one of her little toys in the house she bumped into my table the powder scale sits on really hard. It knocked all kinda crap off the dispenser while I was reloading some test loads. Well I didn’t think nothing about it and put everything back and carried on. The next day at the range I was shooting, everything was fine, then bam blown primer and smoke boiling out of the action. I have no doubt the scale was knocked out of calibration. Came home only a handful of shells were left broke them down and started over. Was always mighty cautious after that!