Question for 300 wm or belted mag reloaders

[washington121]

So I will do my best to ask you guys a question about my brass and see if anyone has heard of this and if they have know of a solution. Out of 100 nosler brass I have 76 of them won't chamber after resizing full length. They have 4 or 5 reloads.These are usually just bumped back 2 thou after each firing. So I set out and spent a lot of time measuring everything on cases that would chamber and cases that would not chamber. Every case dimension I had was exact from case to case and under sammi specs. Every one but the actual size of the belt. This is not the bulge above the belt this is the actual size of the belt. The fired cases measure .531-.532 and the ones that would not fire measure .534-535. Sammi spec for this dimension is .532. After researching online and racking my own brain I said to hell with it I will grab a Emory nail file and slightly file the belt to see if this is really the problem or if I am missing something else. Well grabbed 2 cases that would not chamber and verified they would not chamber before being hit with the file. I filed down the two belts by hand for a minute or so each and they dropped in and chambered no problem. I will not fire this cases due to safety reasons. So to you guys who reload and deal with 300 wm have you seen or heard of this? If you have is there an actual fix for this and does anyone know what would cause this symptom to occur? Thank you guys appreciate it. Posted in another reloading section as well just trying to find as much input as I can. Thanks guys

 

[dkhunt14]

If the belts are expanding .002 to .003 they are hot loads or soft brass. Maybe carbon in the throat raising pressures. Easy to get carbon with big loads of slow burning powder. Nosler brass can be soft. I Don't like them to expand a half thousandths per firing. Matt

 

[shoot4fun]

My guess is that the dies are not able to give you both .002 shoulder bump and a complete sizing of the case head down to the belt. I always recommend the Innovative Technologies (Larry Willis) collet die for belted magnums. it sizes the case back to SAAMI all the way down to the belt. It should bring those belts back into Saami spec as well.
I shoot a bit of Nosler brass in my 300WM, mostly because I could find it, and the collet die along with annealing have really added a lot of life to those cases.

 

[MagnumManiac]

The Innovative die DOES NOT size the belt. NO DIE sizes the belt.
This is due to soft Nosler brass. It is not great for handling pressures.
The cases you have filed are perfectly safe, the belt is part of the solid case head, if it is expanding, your pressures are too much for that brass.
I have run into this problem with Nosler brass too, no longer will waste my money on it. The best brass I have is 300 pieces of Lapua 300WM from the 80's, when they used to make it. Stumbled onto a deceased estate, 1000 pieces of it! Sold 600, kept 300 for my self.
I normally get .0005" belt expansion, then back off a grain.

Cheers.

 

[washington121]

Ok I just never ran into the expanding belts and was curious about the filing. It's weird I have never had an ejector mark or a stiff bolt lift but I know how that goes. I never measured the growth of the actual belt just cases etc and have not encountered a bulge above the belt while just using a Forster neck and bump die and barely pushing shoulders back. Would the filing for a couple firings be no worries? Mainly elk season is coming up have all my dope velocities worked up and don't have the time to mess
With a new lot of brass and do all the data in time and do all the fire forming!

 

[shoot4fun]

The Innovative die DOES NOT size the belt. NO DIE sizes the belt.
This is due to soft Nosler brass. It is not great for handling pressures.
The cases you have filed are perfectly safe, the belt is part of the solid case head, if it is expanding, your pressures are too much for that brass.
I have run into this problem with Nosler brass too, no longer will waste my money on it. The best brass I have is 300 pieces of Lapua 300WM from the 80's, when they used to make it. Stumbled onto a deceased estate, 1000 pieces of it! Sold 600, kept 300 for my self.
I normally get .0005" belt expansion, then back off a grain.

Cheers.

I never intended to imply the die sizes the belt. It sizes the case all the way down to the belt. As for Nosler brass and pressure, mine (and just my experience) have been loaded 10 to 12 reloads and are still able to load and shoot without any problem. That is with 77 grains Retumbo and a 230 OTM Hybrid.

 

[washington121]

Ya my brass shows no other problems besides the growth of the belt. 78 grains of r-26 behind a 215 hybrids seated out around 3.7xx. I have now hear from a few people that the filing of the belt is safe so I will probably do that and see if I can get to 10 reloads with this brass.

 

[Nvreloader]

W121

I had the same problem with my Ruger 77, 7 mag,

If I use the FL sizer to get the area just above the belt to fit the chamber, then I would shorten the OAL, setting the shoulders back and got case body separations.

I started playing around with an RCBS file trim die,
and found I could resize the area just in front of the belt and set the shoulders back .002" from my chamber length, at the same time, by careful adjustments .

Works very well, for me. YMMV.

The other thing I did was get a RCBS FL die, used the chop saw/lathe,
to cut the FL die off about 1/16" below the shoulder junction,
de burred and polished the cut off edge etc.

By carefully setting the die up, I can resize the total case length,
to fit my chamber spec's and NOT touch the shoulder angle.

Note:
This will case the case length to grow several thousands,
and have to set the shoulder dimension back to fit the chamber,
with the file trim die.

HTH,

Tia,
Don

 

[ab_bentley]

W121

I had the same problem with my Ruger 77, 7 mag,

If I use the FL sizer to get the area just above the belt to fit the chamber, then I would shorten the OAL, setting the shoulders back and got case body separations.

I started playing around with an RCBS file trim die,
and found I could resize the area just in front of the belt and set the shoulders back .002" from my chamber length, at the same time, by careful adjustments .

Works very well, for me. YMMV.

The other thing I did was get a RCBS FL die, used the chop saw/lathe,
to cut the FL die off about 1/16" below the shoulder junction,
de burred and polished the cut off edge etc.

By carefully setting the die up, I can resize the total case length,
to fit my chamber spec's and NOT touch the shoulder angle.

Note:
This will case the case length to grow several thousands,
and have to set the shoulder dimension back to fit the chamber,
with the file trim die.

HTH,

Tia,
Don

Larry Willis die, problem solved.

Adam

 

[Nvreloader]

Adam

Not $9.95, included shipping for FL size die.....

Tia,
Don

Larry Willis die, problem solved.

Adam

 

[Zero333]

The Innovative body collet die might work for you. If it sizes the case right above the belt, it could slightly force the belt to re-adjust it's angle enough to chamber.

If your brass has been reloaded a few times and shot only in this one problematic chamber, I'm sure either your loads were hot or the brass sucks. Or both.

Remember when we size brass, we are displacing it's shape, so when we bump the shoulders only (as with a bump die), the brass has to flow somewhere. And if the body isn't supported, it will bulge. This might not cause a belt to expand, but it's something to keep in mind.

 

[washington121]

Ya I get the bulge and how the Forster bump die could cause displacement causing the bulge. I have been wondering if it would cause the bulge after firing. Especially during some summer shooting when the temps were hotter but still never encountered a sticky bolt or ejector marks in my hottest shooting weather in the pnw. I measured every dimension to the best wm case dimensions that I could and all them checked out under sammi spec besides the size of the belt. After hunting season I will take a new lot of nosler brass and do a load tweak while measuring growth of belt to now look at it and see what it starts at brand new and how it grows after each firing. Just never something I paid attention to. I measured above the belt looking for the bulge to check growth after each firing but never just the actual belt. You always learn something and that's why I posted asking. Maybe down the road this also helps somebody out as well

 

[Ledd Slinger]

Problem isnt the brass. Usually its because the die isn't matching up with the chamber.

The Larry Willis Innovative Technologies die works. I had the same exact problem on a belted mag. Just one pass on the IT die and haven't had to do it again.

Could grind your shell holder down a bit too as long as you're not giving yourself excessive headspacing.

 

[sanus]

So I will do my best to ask you guys a question about my brass and see if anyone has heard of this and if they have know of a solution. Out of 100 nosler brass I have 76 of them won't chamber after resizing full length. They have 4 or 5 reloads.These are usually just bumped back 2 thou after each firing. So I set out and spent a lot of time measuring everything on cases that would chamber and cases that would not chamber. Every case dimension I had was exact from case to case and under sammi specs. Every one but the actual size of the belt. This is not the bulge above the belt this is the actual size of the belt. The fired cases measure .531-.532 and the ones that would not fire measure .534-535. Sammi spec for this dimension is .532. After researching online and racking my own brain I said to hell with it I will grab a Emory nail file and slightly file the belt to see if this is really the problem or if I am missing something else. Well grabbed 2 cases that would not chamber and verified they would not chamber before being hit with the file. I filed down the two belts by hand for a minute or so each and they dropped in and chambered no problem. I will not fire this cases due to safety reasons. So to you guys who reload and deal with 300 wm have you seen or heard of this? If you have is there an actual fix for this and does anyone know what would cause this symptom to occur? Thank you guys appreciate it. Posted in another reloading section as well just trying to find as much input as I can. Thanks guys

I know this one was from a few years back but I’ve also had the same issue with the belt expanding on Sako brass.

I don’t have the issue on hornady or federal brass.

so I cut a few cases open - in half and can see the design of the sako brass is not reinforced up to the external belt but it is on the federal and hornady brass.


I took a few pics and will try to upload them.


Seems like it’s a design flaw in sako brass. I have heard that the Norma brass is the same as sako and maybe from the same factory. I will cut a norma case at some stage and compare it to the sako - just don’t have a norma case that has expanded on the belt as yet, so don’t want to waste them by cutting them up just yet. But I will if they expand as well - currently only 2 fired on my norma brass and holding up ok without expansion.


For the time being I have used some emery cloth and then wet and dry and smoothed off some of my sako brass where the belts had expanded. I have them down from 0.5330 to 0.5320 which I understand is max SAAMI spec for the belt on a 300wm. So will shoot them and see if the belt expands anymore - I’ll post what I find out here as well.

I’d be interested if you found anything out as well over the last 4 years since this post was made. Or if others have anything else to add.

Thanks.

 

[TackDriv3r]

I had that issue with virgin brass from Nosler for the 7mm Mag and the 7mm STW in the past, opened one box of each caliber, prepped and loaded and at the range almost half of them would not chamber at all. Went home and pulled bullets and resized again, tried to chamber , still same thing. So i used a marker and marked the forward part of the belts, and chambered it and it left a marking on the front part of the belt where it made contact. Switched to Norma brass and problem solved.

 

[Zero333]

I know this one was from a few years back but I’ve also had the same issue with the belt expanding on Sako brass.

I don’t have the issue on hornady or federal brass.

so I cut a few cases open - in half and can see the design of the sako brass is not reinforced up to the external belt but it is on the federal and hornady brass.


I took a few pics and will try to upload them.


Seems like it’s a design flaw in sako brass. I have heard that the Norma brass is the same as sako and maybe from the same factory. I will cut a norma case at some stage and compare it to the sako - just don’t have a norma case that has expanded on the belt as yet, so don’t want to waste them by cutting them up just yet. But I will if they expand as well - currently only 2 fired on my norma brass and holding up ok without expansion.


For the time being I have used some emery cloth and then wet and dry and smoothed off some of my sako brass where the belts had expanded. I have them down from 0.5330 to 0.5320 which I understand is max SAAMI spec for the belt on a 300wm. So will shoot them and see if the belt expands anymore - I’ll post what I find out here as well.

I’d be interested if you found anything out as well over the last 4 years since this post was made. Or if others have anything else to add.

Thanks.

Thanks for the pics... they tell the story for themselves.
The Hornady brass looks like it's thinning above the belt a little, while the F.C. brass looks perfect.,
It's clear the Norma (Sako) brass looks the most uniform but with the least meat behind the belt, and it's primer pockets could loosen faster than the others.

I've been most satisfied with F.C. brass for my 300winmags.

After several reloads I sacrificed once of the F.C. cases to see how it looks inside... Cut it open with a dremel cut off wheel...

 

[rogn]

Since your nailfile is only removing a minimal amount of brass, sounds like anyhow, you only need to move things a minimal distance. Since were discussing rube Goldberg ways of "fixing" The silly belted brass why not just put the offending brass on a smooth flat steel plate and place a smooth steel bar on the case head end and with a small amount of downward pressure roll the case back and forth a time or two. Repeat with a tad more pressure if the first try doesnt work. All you are trying to do is move the slightly flared, displaced belt. Almost no cost and the result is the same as all the complex formulas mentioned.

I only have one belted rifle and if the case shape wasnt so goofy it would be a 300SPC today, but he shoulder is a bit too far into useful space.
As an aside the Hornady brass I got when I got the rifle is rally pretty poor stuff, both soft and dimensional. The bag of Winny brass I finally found is ten times better.
Why do we still mess with this antique belted case is beyond me now that there are better alternatives.

 

[sanus]

Anyway I bought the Larry Willis die and it does sort the issue.

 

[Dgd6mm]

I know if you search the archives there is good information on sizing the. 300wm. A X member by the screen name Catshooter has excellent information.

 

[Dusty Stevens]

Sounds like your chamber has too much bolt nose spacing or too loose there