Necking 30-06 to 25-06 results in blown primer

[CBS]

I had a Remington action rebarreled to 25-06 because I have ample 30-06 brass hoping to resize and shoot. This is supposed to be a kids gun with low recoil with the addition of a brake. It hasn't been that easy. Resizing leaves a donut that will still chamber stifly. apparently the chamber pressure is high enough to blow a primer about 3-4 gains under my expected max load.

Questions:
- do I need to fire form the brass before working up a load? I was hoping to avoid this.
- is my powder just too fast?
- could my necks be too thick?

I'm using 115 berger, rl26, in a 10 twist barrel hoping to get it to stabilize. I'm nowhere near the lands.

I don't want to waste time and precious supplies trying to reinvent this wheel. I'm hoping for some experience to let me know which direction to head from here.

 

[Ross1147]

I've done this before and haven't had the issues you're talking about. Did you turn the necks after sizing to .257? If not, I bet that's where the issue lies. Probably not enough clearance in the throat for the thick necks to release the bullet and you're building pressure.

 

[Ross1147]

Sorry to finish answering you questions RL 26 is not to fast for that cartridge, if anything it's probably too slow.

I would initially fireform before building up to find max pressure, but with the scarcity of components that may not be achievable?

I'd turn necks then go from there.

 

[Hugnot]

Try fitting a .257 bullet into the neck of a fired .25-06 case. If it does not fit easily, like slip fit, the necks will need turning. Reamers vary in dimensions & the reamer that made your .25-06 chamber did not provide enough neck clearance for unturned necks formed from .30-06 brass.

 

[ButterBean]

Try fitting a .257 bullet into the neck of a fired .25-06 case. If it does not fit easily, like slip fit, the necks will need turning. Reamers vary in dimensions & the reamer that made your .25-06 chamber did not provide enough neck clearance for unturned necks.

In my experience the necks will need turned regardless

 

[del2les]

Most likely, thick necks. I have seen a few fatory chambers that were sloppy enough to not need turning, but most customs will require some.

 

[Hugnot]

Neck turning needs to be done carefully, turning necks beyond a certain point will prevent adequate neck tension to hold bullets upon neck sizing - the neck walls will be too thin and neck sizing compression will not provide enough neck tension to hold the loaded bullet. A slip fit will indicate adequate clearance between neck and chamber. Turning necks will also make for less run-out meaning your ammo will be more concentric and accurate Upon neck turning it is common to see one side that has removed brass and the other untouched.

My suggestion would be to turn a few necks so they just clean up, fire a few rounds with starting loads, check for slip fit, size including neck size, then check for adequate & uniform neck tension to hold bullets.

 

[antelopedundee]

Try fitting a .257 bullet into the neck of a fired .25-06 case. If it does not fit easily, like slip fit, the necks will need turning. Reamers vary in dimensions & the reamer that made your .25-06 chamber did not provide enough neck clearance for unturned necks.

Does a reamer manufacturer allow for and consider all logical sources for brass like necking down .30-06 cases when .25-06 cases are generally readily available?

 

[MagnumManiac]

It may not be the donut causing the stiff chambering, and no, reamers are not made to accomodate where the brass comes from.
You need to measure a loaded rounds neck, then measure a fired case. This will tell you without any doubts how much clearance you have. Also measure case length, a necked down case normally grows longer and thicker.

Cheers.

 

[ButterBean]

Neck turning needs to be done carefully, turning necks beyond a certain point will prevent adequate neck tension to hold bullets upon neck sizing - the neck walls will be too thin and neck sizing compression will not provide enough neck tension to hold the loaded bullet. A slip fit will indicate adequate clearance between neck and chamber. Turning necks will also make for less run-out meaning your ammo will be more concentric and accurate Upon neck turning it is common to see one side that has removed brass and the other untouched.

My suggestion would be to turn a few necks so they just clean up, fire a few rounds with starting loads, check for slip fit, size including neck size, then check for adequate & uniform neck tension to hold bullets.

.012-.014 is target neck thickness

 

[Hugnot]

Does a reamer manufacturer allow for and consider all logical sources for brass like necking down .30-06 cases when .25-06 cases are generally readily available?

The neck diameter of a .25-06 reamer should be .290 inches.

 

[Carlos88]

Does a reamer manufacturer allow for and consider all logical sources for brass like necking down .30-06 cases when .25-06 cases are generally readily available?

No. They use SAAMI data.

 

[budlight]

I make .243 out of .308 so it's always inside and outside neck turning. 25-06 is the same problem. making 25-06 Nothing needs to be fire formed

R-26 is one of the best powders for you. Are you loading about 50 gr. ?

 

[Ckgworks]

Making 260 rem brass from LC 308 required neck turning for me, otherwise over-pressure signs were there. Take one of the fired cases and try putting a bullet in it. It should fit if you have sufficient neck clearance on your brass..... on the 260, it was very tight.