Case mouth stretch in fired 222 brass

[gordphillipps]

My once fired brass, Rem. Win, or Fed light loads open up so much a flat base 52 grn. 224 bullet will drop into the case before resizing. Same not true with my 220 swift. Is this an indicator of the chamber worn?

 

[ar10ar15man]

no

 

[gordphillipps]

Normal?

 

[ar10ar15man]

Normal?

yes

 

[ar10ar15man]

your other rifle sounds like the problem.
lack of neck clearance

 

[243winxb]

Slow burn rate powder and light bullets may not fully expand the necks on firing. Example- 243 win , 68 gr Berger bullet, IMR 4350 powder.

Near maximum loads are needed to fully expand the necks.

The hardness of the brass is another reason expansion may be different. . Annealed brass will expand easier.

Look up the chamber specifications of both. https://saami.org

 

[MagnumManiac]

There needs to be .003" minimum clearance between a sized/loaded rounds neck and the chamber.
The maximum should be .006", but have seen factory chambers larger.
A tight neck, say .002" MAY increase pressure beyond normal 'tracking', this occurred to me in several instances of 'turned-neck' chambers.
I no longer order 'turned-neck' chambers and order my neck clearance AFTER buying a batch of brass for that barrel with .003" clearance. My best barrel has a neck clearance of .004", just as an example.
Pressure spikes are not conducive to tuning a load.

Cheers.

 

[Mikecr]

Is this an indicator of the chamber worn?

Chambers don't wear.

Necks expand into your neck clearance and then spring back up to a thou. Where your neck clearance puts the spring back ID greater than cal, then you no longer have interference for cal. It's normal.

I don't know that there is any 'problem' with your 220 clearance, and I don't have a problem with tighter clearances myself. I often set my clearances to spring back with interference, and even run a fitted chamber for one cartridge. With this, I do not resize necks in reloading. No issues with pressure, and there is no reason there ever would be.

What grips a bullet is a set area of spring back against seated bullet bearing. This spring back force is not squeezing bullets. Trust me, those bullets stay at cal diameter, and necks gripping them reach no less than cal. Given this, and so much as a billionth of an inch neck expansion (or less), bullets are in fact freely released. And this is an absolute, there is not more or less freely released.

As long as neck ODs are not in interference with chamber,, that is, providing for any amount of unrestricted expansion, you have clearance. You have to manage at least that whether a little or a lot of clearance, including consideration of fouled ammo/chamber.
Some pros and cons in clearance choice:
- It's excess neck clearance, and excess chamber end clearance that contributes to higher ES. Not tighter clearances. The quicker necks seal to chamber, the better.
- High loaded runout can result in high chambered pressure points, if there is not enough clearance to relieve this. But keep in mind --->
- Tighter neck clearance means less working of necks with reloading cycles, which makes for easier management of consistent tension and lower runout.
- Guns can shoot just fine with either tight or loose clearances, either by virtue of planning, or purely by luck.

The clearance notions I've seen over the years seems to follow similar notions with racing engine clearances, which I observed in the past. Mechanics, 'Shade Tree' and formula one alike insisted that more & more clearances were needed to reduce incidents of failure. Then Smokey Yunick committed the ultimate sin; he tested it, and showed the world they were all wrong. That clearances were already too loose.
We used to feel lucky to get 100Kmi out of family car engines.. Thank You Smokey, and NASCAR, for engines built far better.

 

[gordphillipps]

Chambers don't wear.

Necks expand into your neck clearance and then spring back up to a thou. Where your neck clearance puts the spring back ID greater than cal, then you no longer have interference for cal. It's normal.

I don't know that there is any 'problem' with your 220 clearance, and I don't have a problem with tighter clearances myself. I often set my clearances to spring back with interference, and even run a fitted chamber for one cartridge. With this, I do not resize necks in reloading. No issues with pressure, and there is no reason there ever would be.

What grips a bullet is a set area of spring back against seated bullet bearing. This spring back force is not squeezing bullets. Trust me, those bullets stay at cal diameter, and necks gripping them reach no less than cal. Given this, and so much as a billionth of an inch neck expansion (or less), bullets are in fact freely released. And this is an absolute, there is not more or less freely released.

As long as neck ODs are not in interference with chamber,, that is, providing for any amount of unrestricted expansion, you have clearance. You have to manage at least that whether a little or a lot of clearance, including consideration of fouled ammo/chamber.
Some pros and cons in clearance choice:
- It's excess neck clearance, and excess chamber end clearance that contributes to higher ES. Not tighter clearances. The quicker necks seal to chamber, the better.
- High loaded runout can result in high chambered pressure points, if there is not enough clearance to relieve this. But keep in mind --->
- Tighter neck clearance means less working of necks with reloading cycles, which makes for easier management of consistent tension and lower runout.
- Guns can shoot just fine with either tight or loose clearances, either by virtue of planning, or purely by luck.

The clearance notions I've seen over the years seems to follow similar notions with racing engine clearances, which I observed in the past. Mechanics, 'Shade Tree' and formula one alike insisted that more & more clearances were needed to reduce incidents of failure. Then Smokey Yunick committed the ultimate sin; he tested it, and showed the world they were all wrong. That clearances were already too loose.
We used to feel lucky to get 100Kmi out of family car engines.. Thank You Smokey, and NASCAR, for engines built far better.

Thanks guys you've been a great help. It's just it was the first time I experienced it and this 600 is a great little carbine.

 

[ronstone09]

My once fired brass, Rem. Win, or Fed light loads open up so much a flat base 52 grn. 224 bullet will drop into the case before resizing. Same not true with my 220 swift. Is this an indicator of the chamber worn?

I would think thats normal before sizing ! after sizing if you have that problem then you need the get a smaller bushing for your die ! You want around 2 thousands tightness in your neck for seating depending on your rifle !

 

[HobieH3]

Chambers don't wear.

Necks expand into your neck clearance and then spring back up to a thou. Where your neck clearance puts the spring back ID greater than cal, then you no longer have interference for cal. It's normal.

I don't know that there is any 'problem' with your 220 clearance, and I don't have a problem with tighter clearances myself. I often set my clearances to spring back with interference, and even run a fitted chamber for one cartridge. With this, I do not resize necks in reloading. No issues with pressure, and there is no reason there ever would be.

What grips a bullet is a set area of spring back against seated bullet bearing. This spring back force is not squeezing bullets. Trust me, those bullets stay at cal diameter, and necks gripping them reach no less than cal. Given this, and so much as a billionth of an inch neck expansion (or less), bullets are in fact freely released. And this is an absolute, there is not more or less freely released.

As long as neck ODs are not in interference with chamber,, that is, providing for any amount of unrestricted expansion, you have clearance. You have to manage at least that whether a little or a lot of clearance, including consideration of fouled ammo/chamber.
Some pros and cons in clearance choice:
- It's excess neck clearance, and excess chamber end clearance that contributes to higher ES. Not tighter clearances. The quicker necks seal to chamber, the better.
- High loaded runout can result in high chambered pressure points, if there is not enough clearance to relieve this. But keep in mind --->
- Tighter neck clearance means less working of necks with reloading cycles, which makes for easier management of consistent tension and lower runout.
- Guns can shoot just fine with either tight or loose clearances, either by virtue of planning, or purely by luck.

The clearance notions I've seen over the years seems to follow similar notions with racing engine clearances, which I observed in the past. Mechanics, 'Shade Tree' and formula one alike insisted that more & more clearances were needed to reduce incidents of failure. Then Smokey Yunick committed the ultimate sin; he tested it, and showed the world they were all wrong. That clearances were already too loose.
We used to feel lucky to get 100Kmi out of family car engines.. Thank You Smokey, and NASCAR, for engines built far better.

+1 Smokey was a genius in his field

 

[gordphillipps]

Ole Smokey and Arkus Duntov built the perfect Mouse that roared! Smokey built a 3/4 size race car that fooled everyone for a while!

 

[ar10ar15man]

7/8....not 3/4

Ole Smokey and Arkus Duntov built the perfect Mouse that roared! Smokey built a 3/4 size race car that fooled everyone for a while!

 

[gordphillipps]

7/8....not 3/4

I figured that was wrong when I posted. I've got a great memory, but short!lol Smart ole cookie. I remember his shop and his cowboy hat and three day beard.