Misfires

[jlanecr500]

Cci large rifle. Probably shot 600 thru the brick at this point

That is likely your problem. I stay away from CCI rifle primers because they are harder than the other brands. I have also experienced misfires with them. Your firing pin spring just doesn't have what is needed for them or headspace is incorrect. You can check the headspace with one that misfires. Put a piece of masking tape on the face of the cartridge. Trim it around the case head. If it chambers, your cartridge neck is short. Headspace is measured from the neck midpoint to cartridge face. Case length is another animal.

 

[Jcalder]

That is likely your problem. I stay away from CCI rifle primers because they are harder than the other brands. I have also experienced misfires with them. Your firing pin spring just doesn't have what is needed for them or headspace is incorrect. You can check the headspace with one that misfires. Put a piece of masking tape on the face of the cartridge. Trim it around the case head. If it chambers, your cartridge neck is short. Headspace is measured from the neck midpoint to cartridge face. Case length is another animal.

A fired case measure 2.040. The misfires measure 2.037

 

[jlanecr500]

A fired case measure 2.040. The misfires measure 2.037

How are you measuring case length ? A Hornady case comparator measures from the proper place on the neck. Add neck diameter and case diameter. Then divide by 2. That diameter is the point on the neck at which headspace is measured from face of cartridge. On the 25-06 that diameter is .375" and the minimum distance to the cartridge face is 2.0487". That would make your cartridge .010" short.
If you can chamber the short cartridge with a piece of masking tape on its face, it is too short and for every .010" short, your firing pin strike will be shallow too.

 

[Jcalder]

How are you measuring case length ? A Hornady case comparator measures from the proper place on the neck. Add neck diameter and case diameter. Then divide by 2. That diameter is the point on the neck at which headspace is measured from face of cartridge. On the 25-06 that diameter is .375" and the minimum distance to the cartridge face is 2.0487". That would make your cartridge .010" short.
If you can chamber the short cartridge with a piece of masking tape on its face, it is too short and for every .010" short, your firing pin strike will be shallow too.
View attachment 150255

I have a Hornady headspace tool

 

[jlanecr500]

I have a Hornady headspace tool

Maybe the neck hasn't yet taken on the proper neck angle. I've necked down 30-06 brass but never 270. 270 has a different neck angle. The 25-06 was derived from a 30-06 case.

 

[Jcalder]

Maybe the neck hasn't yet taken on the proper neck angle. I've necked down 30-06 brass but never 270. 270 has a different neck angle. The 25-06 was derived from a 30-06 case.

Correct me where I'm wrong. All have the same body/shoulder intersection. The angle is slightly different. I've measured a lot of the brass and they're all within .005". Sized fired and new brass. Think my longest headspaced piece is around 2.041 and my sized stuff is 2.037 I'll continue until I figure it out once ball is over this week

 

[RockMcL]

Since you converted the brass, suggest mic the shoulder start and shoulder end compared to 2506 spec. If you still have problems after sizing I would cast the chamber. I have not "played" recently but I always used to chamber cast when developing brass and or rechambering.
(And/or fire form to chamber, resize and load)

Sometimes you can see, oh that ain't right...

If I am sticking bullets, by the way, either my load data was for a different bullet/ojive or my oal was just wrong, or my chamber was not what I thought it was.


My "failures" when primers seated properly has always been shoulder... just my experience.

 

[Jcalder]

Since you converted the brass, suggest mic the shoulder start and shoulder end compared to 2506 spec. If you still have problems after sizing I would cast the chamber. I have not "played" recently but I always used to chamber cast when developing brass and or rechambering.
(And/or fire form to chamber, resize and load)

Sometimes you can see, oh that ain't right...

If I am sticking bullets, by the way, either my load data was for a different bullet/ojive or my oal was just wrong, or my chamber was not what I thought it was.


My "failures" when primers seated properly has always been shoulder... just my experience.

I've measured all I can. The best I can come up with is about .004" difference between the sized cases and a fired case in that rifle. Jlanecr500 suggested using tape on the headstamp to figure out the headspace. The fired cases would accept 2 pieces or blue painters tape, and the sized would take 3 to get a very tight bolt close. Guessing the spring back is why I got the 2 layers on the case head of the fired case.