Case bulge in belted magnums

[AlaskaHunter]

Case bulge is supposed to be common in belted magnums.
I have not seen it in my .300 H & H.
I asked in a .300 H & H forum if anyone has experienced case bulge after repeated resizing....no one did.
Why?
Did we get lucky?
Does the gentle shoulder (7.5 degrees) have something to do with it?
Is it because we don't load near the max?

As an example, I got 11 resizes before retiring brass,
each time reloading 180 gr Nozler partitions,
64.0 gr IMR4831 (88% case capacity, ~2860 fps)
Here is the reloading history on that brass (now retired)
1993--virgin brass, fire-form
1994--resize, fire, anneal & resize
1995--fire, resize, fire, resize
1996-2003 sheep hunting years, no reloading of 300 H & H
2003-fire, anneal & resize, fire, resize
2004--fire, resize, fire, resize, fire resize
2005--anneal & resize, fire, resize
retire cases
Those cases still fit my chamber smoothly.
Why no case bulge?

 

[antelopedundee]

Something being common doesn't mean always. Maybe your die has something to do with it. Count your blessings.

 

[std7mag]

I don't have that issue with my 7mm Rem Mag either.
After full length sizing when new, i collet neck size only.

 

[S13tsilvia]

havent seen it either in my 338, 300 weatherby or 470. Full length resize each time and they are not run at extreme speeds may help.

 

[338reddog]

I have a die that resizes the bulge. One end to tell if the case has bulged. I have checked many of case in 7mag, 300 wby and 338wm. Maybe 10% needed sizing. Im not really sure how much of a problem it really is.

 

[338reddog]

Case bulge is supposed to be common in belted magnums.
I have not seen it in my .300 H & H.
I asked in a .300 H & H forum if anyone has experienced case bulge after repeated resizing....no one did.
Why?
Did we get lucky?
Does the gentle shoulder (7.5 degrees) have something to do with it?
Is it because we don't load near the max?

As an example, I got 11 resizes before retiring brass,
each time reloading 180 gr Nozler partitions,
64.0 gr IMR4831 (88% case capacity, ~2860 fps)
Here is the reloading history on that brass (now retired)
1993--virgin brass, fire-form
1994--resize, fire, anneal & resize
1995--fire, resize, fire, resize
1996-2003 sheep hunting years, no reloading of 300 H & H
2003-fire, anneal & resize, fire, resize
2004--fire, resize, fire, resize, fire resize
2005--anneal & resize, fire, resize
retire cases
Those cases still fit my chamber smoothly.
Why no case bulge?

Also your basically running a 30/06 in the h&h mag( not a bad thing) Lower pressure may have helped

 

[Don Fischer]

Case bulge? You mean at the head? What I have seen there is separation start. Happened to me on a 7mm Rem Mag years ago and I found the answer to eliminating it was to partial size after the first shot. Have only had two belted case cartridge's since, both 338 win mag's, and have never even considered anything other than partial sizing. As it was explained to me, belted case's headspace on that belt. As a result some chamber's have a sloppy chamber and to correct for it, partial size moving the headspace to the shoulder. Still also headspaces of the belt but going to the shoulder eliminates the possibility of head separation problems. If either of my ld 338 mags had sloppy chamber's, I'll never know! No need or desire to find out!

After shooting a friends 22 Hornet a bunch I'd apply the same theory to it. Resize to headspace on the shoulder. In fact I'd go farther with a case with a shoulder like the hornet and improve the case to have a good shoulder the size to.

 

[Don Fischer]

Case bulge? You mean at the head? What I have seen there is separation start. Happened to me on a 7mm Rem Mag years ago and I found the answer to eliminating it was to partial size after the first shot. Have only had two belted case cartridge's since, both 338 win mag's, and have never even considered anything other than partial sizing. As it was explained to me, belted case's headspace on that belt. As a result some chamber's have a sloppy chamber and to correct for it, partial size moving the headspace to the shoulder. Still also headspaces of the belt but going to the shoulder eliminates the possibility of head separation problems. If either of my ld 338 mags had sloppy chamber's, I'll never know! No need or desire to find out!

After shooting a friends 22 Hornet a bunch I'd apply the same theory to it. Resize to headspace on the shoulder. In fact I'd go farther with a case with a shoulder like the hornet and improve the case to have a good shoulder the size to. I suspect all rimmed case's could use that partial sizing with no problem. A partial sized case fit's your chamber!

 

[338reddog]

Case bulge? You mean at the head? What I have seen there is separation start. Happened to me on a 7mm Rem Mag years ago and I found the answer to eliminating it was to partial size after the first shot. Have only had two belted case cartridge's since, both 338 win mag's, and have never even considered anything other than partial sizing. As it was explained to me, belted case's headspace on that belt. As a result some chamber's have a sloppy chamber and to correct for it, partial size moving the headspace to the shoulder. Still also headspaces of the belt but going to the shoulder eliminates the possibility of head separation problems. If either of my ld 338 mags had sloppy chamber's, I'll never know! No need or desire to find out!

After shooting a friends 22 Hornet a bunch I'd apply the same theory to it. Resize to headspace on the shoulder. In fact I'd go farther with a case with a shoulder like the hornet and improve the case to have a good shoulder the size to.

A K horrnet is a good option. My buddy had a hornet rupture in a Ruger #3, bent the ejector and split the for end in half.

 

[AlaskaHunter]

Case bulge? You mean at the head? What I have seen there is separation start. Happened to me on a 7mm Rem Mag years ago and I found the answer to eliminating it was to partial size after the first shot. Have only had two belted case cartridge's since, both 338 win mag's, and have never even considered anything other than partial sizing. As it was explained to me, belted case's headspace on that belt. As a result some chamber's have a sloppy chamber and to correct for it, partial size moving the headspace to the shoulder. Still also headspaces of the belt but going to the shoulder eliminates the possibility of head separation problems. If either of my ld 338 mags had sloppy chamber's, I'll never know! No need or desire to find out!

After shooting a friends 22 Hornet a bunch I'd apply the same theory to it. Resize to headspace on the shoulder. In fact I'd go farther with a case with a shoulder like the hornet and improve the case to have a good shoulder the size to.

According to my Speer manual, the H & H cases are the only ones that really need to headspace off the belt due to their gentle shoulders (8.5 degrees) compared to cases like 7mm Rem Mag, 300 Win Mag, 338 Win mag with shoulders of 25 degrees. " H & H are probably the only bottle-necked magnums in current use that really need the case belt because of their shallow shoulder. Others have ample shoulder for headspacing and the belt of these modern cartridges is really superfluous. Yet "belted" and "magnum" have become synonymous that any effort to promote a new magnum cartridge would have slim chance of success, regardless of how good a performer it was". That quote is from my Speer Manual Number 11 (1987), so a historical perspective and things have changed with cartridges such as the Lapua 338 Magnum etc.

 

[WapitiBob]

I see it occasionally in my 7stw but I'm using 81.5 gr of powder. You can buy a special collet die to resize the area at the belt on those that need it. The 300 PRC, although not belted, is starting to see a similar problem as their sizer doesn't get to the btm of the case and the design of the case, chamber, and sizer die are too tight.

 

[Don Fischer]

According to my Speer manual, the H & H cases are the only ones that really need to headspace off the belt due to their gentle shoulders (8.5 degrees) compared to cases like 7mm Rem Mag, 300 Win Mag, 338 Win mag with shoulders of 25 degrees. " H & H are probably the only bottle-necked magnums in current use that really need the case belt because of their shallow shoulder. Others have ample shoulder for headspacing and the belt of these modern cartridges is really superfluous. Yet "belted" and "magnum" have become synonymous that any effort to promote a new magnum cartridge would have slim chance of success, regardless of how good a performer it was". That quote is from my Speer Manual Number 11 (1987), so a historical perspective and things have changed with cartridges such as the Lapua 338 Magnum etc.

I have never used a 30 H&H but I suspect you might be right. But headspacing on the belt the chamber could still be sloppy and the problem could still exist. If you see a ring start to develop around the head of the cartridge, simply neck size a couple time's with the FL die and that should expand the case to where it won't chamber easily. Then FL size just a bit at a time till the case will chamber easily. Possible I think this might not happen as the shoulder is so slopping but I have seen it on the Hornet so would assume it could happen with the 300 H&H also. Hornet headspace's on the rim. Problem is that the sloppy case, if it is, when fired stretches forward away from the head and pulls at the top of the head. Make the case fit and even that sloping shoulder is enough to stop the case from pulling to much from the head.

 

[AlaskaHunter]

Thanks. Yes I full-length resize with a shoulder bump of 0.002".
For the 300 H & H I like the LE Wilson Case Gauge with their micrometer....
more precise than the Hornady comparator and calipers.