When fireing a new cases in a benchrest gun I have loaded the bullet out into the lands to get the case held against the bolt so I got a case perfectly sized to the chamber of that particular rifle. Then neck size only, ocassionaly having to bump the shoulder back a wee bit.
Now my questions are: If a person has a rifle that is chambered for a belted magnum, can the same procedure be used to hold the case against the bolt and allowing the case to fireform to fit that particular chamber? Would such a proceedure help prevent or slow down the case stretching just above the belt that can lead to case head seperation? Would this extend case life of a belted magnum?

Thanks

I've used a false shoulder instead of loading into the lands on a 375H&H, more positive and works great. I ran the case onto a .405" expander, then partial neck sized in a full length die just enough to chamber the empty brass.

Right to left, Factory brass, expanded neck, partial neck sized, final neck sized.

quote:

If a person has a rifle that is chambered for a belted magnum, can the same procedure be used to hold the case against the bolt and allowing the case to fireform to fit that particular chamber?

The simple answer is yes. Or form a false shoulder as stated. I've found that the majority of the excess space is in front of the shoulder not in the belt area. Most people have trouble because they full length resize pushing the shoulder back. While the case still headspaces on the belt it must expand and move forward to fill the chamber.

On my belted cases I don't go to the trouble of jaming the bullet in the lands. I let the first firing headspace on the belt then all loading after than I headspace on the shoulder.

I also follow ramrod when loading belted mags, first firing then partial or neck size.

That first firing with excess shoulder space is the one that does the most damage to a new case with too much headspace.

http://www.larrywillis.com/headspace.html

quote:

Headspace problems are much more common with belted magnum calibers. This is because ammunition manufacturers always make their belted magnum calibers to headspace on the belt. They also leave the shoulder extremely far from contacting the chamber. This causes the first firing of belted cases to stretch quite badly. Your "once fired" case is now stretched considerably and it is weakened at the expansion ring. The good news is that further case damage can be kept to a minimum when handloading belted magnums by setting headspace on the shoulder, just as you would for any rimless caliber.

quote:

That first firing with excess shoulder space is the one that does the most damage to a new case with too much headspace.

I agree 100% with his comment. Just call it lazy. Mag brass for everything I shoot is cheap when I get 5 loading I toss it.
No doubt stopping the stretch first firing would probably increase the life.

I have found that new belted cases have a lot of headspace. Measuring with the Head & Shoulders Gauge, here are some examples:

264 win mag WW cases:
New brass - 4.109" (the measurement doesn't matter, only it's relationship to the other measurements)
Once fired - 4.136"
Twice fired - 4.1385"

338 win mag WW cases:
New brass - 4.0970"
Once fired - 4.1200"
Twice fired - 4.1230"

In these 2 rifles I found that the shoulder measurement after being fired twice is the measurement I want to push the shoulder back to everytime. That is where the case shoulder comes into slight contact with the chamber shoulder.

So with once fired and twice fired brass I only neck size and then I push the shoulder back after the 3rd firing to PFLR.

I don't see how loading the bullet into the lands will keep the case from expanding any differently than loading them off the lands, the case still has to expand the exact same amount in order to get to the shoulder.

quote:

I don't see how loading the bullet into the lands will keep the case from expanding any differently than loading them off the lands, the case still has to expand the exact same amount in order to get to the shoulder.

As I played with forming my blown out 280 which has to move the shoulder forward. I used bullets in the land, false shoulder and since it was a CRF tried COW with only the extractor providing headspace. Then cut them open to look.

With the false shoulder or bullet in the lands it look like the expansion only happened in the shoulder area moving out and forward. With the case held in place by the extractor the case moved forward thinning the web.

Right or wrong I have no idea just my observation.

Well, come to think of it, I guess it could make a difference.

I don't think any belts are manufactured to a tolerance so that by chambering the case the belt would hold the case head tight against the bolt. Nor does the CRF grip the case head tight enough so that the case head is held tight to the bolt with no play. So when the firing pin hits the primer there is going to some movement forward first, then the case will expand to the chamber walls and then the case head will be forced back to the bolt head causing the thinning at the web.

If the bullet is jammed the firing pin will not introduce movement of the case forward so the case head will not move forward and then come back. This might reduce or eliminate thinning at the web.

So it might be a good idea to jam the bullets for the first 2 or 3 firings until you can keep the case head from moving forward by shoulder contact and PFLR.

Might extend case life by reducing thinning of the web that happens during the first 2 or 3 firings.

Question, when you jam bullets do you reduce the load in order to keep pressures down?

Is this an epiphany or a brain fart?

A very knowledgable reloading friend told me bullets into the lands will increase pressure by a little over 7kpsi, so you definately wouldn't want to use near max loads on that first firing. Using the false shoulder method wouldn't make much if any difference.

quote:

Question, when you jam bullets do you reduce the load in order to keep pressures down?

Well the only time I now jam the bullet in (more often form a false shoulder) is for my wildcat. In that case I use a med heavy parent load of faster powder.

If I was just wanting to do the small amount of forming on a belted case by jaming the bullet I would reduce load. False shoulder I wouldn't.

Like I said for my magnum brass I fire and then headspace on the shoulder then toss after about 5 firings. If I can add right. Normal mag brass is around 50-55 cents. To fireform you need bullet (.2-.25) powder (.17-.2) and primer (.03) So you spend .40-.48 plus time plus barrel wear so you can get a few extra firings.

quote:

Headspace problems are much more common with belted magnum calibers. This is because ammunition manufacturers always make their belted magnum calibers to headspace on the belt. They also leave the shoulder extremely far from contacting the chamber. This causes the first firing of belted cases to stretch quite badly. Your "once fired" case is now stretched considerably and it is weakened at the expansion ring. The good news is that further case damage can be kept to a minimum when handloading belted magnums by setting headspace on the shoulder, just as you would for any rimless caliber.

I only find this to be true IF the headspace of the unfired brass is not tight (minimal) in the chamber to begin with.

It can be avoided by running the reamer into the new barrel just far enough to accept the brass you are going to use, when originally chambering the rifle. That's pretty much how I chamber ALL my own personal rifles, when for belted or rimmed rounds.

Once in a while you may also need to cut or grind a tiny bit off the base of your sizing die, but the first firing will tell you if that is needed or not.

The downside is that a new lot of brass bought later may have the belts/rims a bit too thick to chamber with reasonable effort. But then, if your first lot is 300 rounds, you will very likely never need a new lot anyway. With a good tight fit and no setting back of the shoulder, you may very likely find 8-10 reloads quite reasonably obtained.

quote:

Originally posted by Alberta Canuck:
I only find this to be true IF the headspace of the unfired brass is not tight (minimal) in the chamber to begin with.

It can be avoided by running the reamer into the new barrel just far enough to accept the brass you are going to use, when originally chambering the rifle. That's pretty much how I chamber ALL my own personal rifles, when for belted or rimmed rounds.

Once in a while you may also need to cut or grind a tiny bit off the base of your sizing die, but the first firing will tell you if that is needed or not.

The downside is that a new lot of brass bought later may have the belts/rims a bit too thick to chamber with reasonable effort. But then, if your first lot is 300 rounds, you will very likely never need a new lot anyway. With a good tight fit and no setting back of the shoulder, you may very likely find 8-10 reloads quite reasonably obtained.

The topic in the quote pertains to existing chambers that have excessive headspace and/or shoulder space, and one way of dealing with it with an expensive die, not building a rifle in the first place. If the chamber was cut properly in the first place, or the brass with the belt in the proper spec, we wouldn't be discussing it!!

http://www.larrywillis.com/headspace.html

I use 300 Win Winchester brass to make my 7mm Rem cases. You use a .338 Win die to push the shoulder back first then a 7mm Rem die to set your final headspace on the shoulder at 0 in your gun. I found that I had to anneal the necks after this with a candle to get a consistant neck turn .
Glenn

[QUOTE]Originally posted by wrongtarget:

The topic in the quote pertains to existing chambers that have excessive headspace and/or shoulder space, QUOTE]


Well, I still find the quote to be not totally accurate in its presumptions, when I compare it to my own experience.

When a new round is fired in a chamber with both too long a spacing to the shoulder and excessive headspace, several things appear to happen.

1. The cartridge is driven forward until the front of the belt hits the chamber, and the primer is then ignited, and then the rest of the charge.

2 - The case walls swell, freezing the main body of the cartridge temporarily in place.

3 - Then the shoulder is blown forward and outward, filling the front of the chamber and re-shaping the front of the case.

4- At the same time as "3" above, the belt and head of the case are blown back until in full contact with the face of the bolt.

5 - During both 3 & 4, the main body of the case does not move, as pressure still holds it against the chamber walls. It is this lack of case body motion while the case head moves back to the bolt face which causes the problem of stretching near the base and eventually causes premature failure there.

6 - That particular movement of the case head CAN be prevented by forming a false shoulder which prevents the case from moving forward prior to ignition. If that is done, the stretching at the case head will be minimized and/or eliminated even though the shoulder may still have to blow outward to fill the front of the case.



This all, of course, is not peculiar just to belted cases.

SAAMI dimensions for chambers and and loaded cartridges generally leave about .003" between shoulders of cartridges and chambers, so that any cartridge loaded to SAAMI specs will fit into any SAAMI dimensioned rifle chamber.

If one then adds on a manufacturing tolerance of .003" in the construction of rifle chambers, and another .003" tolerance in the manufacture of ammunition, one MIGHT OCCASIONALLY end up with a tolerance "stack" of .009", which may cause brass stretching and reduced case life there too.

So, for best brass life, I suspect one might reduce loss if they made a habit of setting the bullet forward against the lands and/or using a false shoulder in the first loading of the brass, regardless whether loading belted or unbelted new brass.

All other shooters are, of course, welcome to view the circumstance differently and act accordingly. That, however is what my 50+ years of reloading has suggested to me.

Yes, you can do it that way. But I like wrongtarget's method better. It is a good way to make brass for such things as the Gibbs line too!

Good post AC

I am still building my database so I don't have shoulder measurements on all my rifles but to run down the list that I do have:

Shoulder measurements from new cases to fully fire formed
Win Mod 70 264 win mag - .0295"
Beretta Mato 338 win mag - .0260"
Hart barreled 280AI - .0170"
Steyr 30-06 - .0115"
Remington 22-250 - .0100"
Weatherby 280 rem - .003"
Sako 30-06 - .003"

So it seems like the belted magnum cases have the largest headspace on new cases, those were both WW cases. The 280AI cases were Nosler and the manufacturer probably wanted to give plenty of headspace in order to fit the custom chambers in that caliber. The 30-06's and 22-250 were Nosler cases and the 280 rem cases were Remington.

Of course all this varies according to chamber and case manufacturer but in general I would say that belted cases have 2 time or more the headspace of non belted cases and that is where the biggest problem would be.

From now on I am going to jam the bullets in belted and non belted cases for the first firing and see what kind of measurements I get.

Okay, so I did a little test.

I took 8 new 338 win mag cases and loaded them with 72.5 gr RL19 and the 225 gr Accubond. On 4 of them I seated the bullet .020" off the lands and the other 4 I seated the bullet to just touch the lands.

The test was to see if the jammed bullets would lead to the shoulder being pushed further forward.

• New cases had a shoulder measurement of 4.097"
  
• The 4 cases that had the bullet seated .020" off had a shoulder measurement of 4.121" after firing
  
• The 4 cases that had the bullet seated into the lands had a shoulder measurement of 4.121" after firing
  
• All 8 fired cases were about the same OAL

So my conclusion so far is that seating into the lands does not move the shoulder any further forward than seating off the lands. BTW, a crush fit on the shoulder with this rifle happens at 4.124".

Now the real shocker



I think I might just load up a whole bunch of those bullets seated right on the lands!