1977 M77 220swift

[BadMatrix]

Sizing the brass has reduced the neck OD. Measure the neck OD on the un-sized brass. If it is larger than .260 that is the problem caused by the brass manufacturer. If it is less than .260 you probably have a severe carbon ring.

Case headspace is a major issue with the Swift. Due to the angle of the shoulder it moves forward with every firing. This is exactly why I told you that you have to resize and push back the shoulder .002 to .003 after every firing. Again, you need to buy a .264 neck bushing and establish datum line on the shoulder and check every piece of brass after firing.

Neck bushing, you mean a case gauge? What a headache. SAAMI headspace is 1.8006-1.8016". I have a target value of 1.8011" but it seems difficult to get there. I am using a Hornandy comparator for the measurements.

 

[AZ10X]

"It is the ammo. I resized one. Cleaned it off and chambered it. The bolt was happy!
I grabbed a non-sized brass and chambered it. The bolt was hard to open and close."

Sizing the brass has reduced the neck OD. Measure the neck OD on the un-sized brass. If it is larger than .260 that is the problem caused by the brass manufacturer. If it is less than .260 you probably have a severe


carbon ring.

Neck bushing, you mean a case gauge? What a headache. SAAMI headspace is 1.8060-1.8016". I have a target value of 1.8011" but it seems difficult to get there. I am using a Hornandy comparator for the measurements.

If this is the gauge, with the correct insert, that you are using your are fine. https://www.hornady.com/headspace-bushings#!/ However, the Hornaday base is a POS from a repeatability point of view. If you are using the Hornady OAL gauage it is for bullet seating depth not case headspace. Neck bushing =
https://www.brownells.com/reloading...g-die-parts-accessories/neck-sizing-bushings/ Forget SAAMI spec which is based on a minimum chamber. Get the measurement from a fired case from your gun. If you find it difficult to get to the correct shoulder set-back buy a shoulder bump die. A F/L die and a shoulder bump die take a little finesse but just go slow and adjust your die with minimal movement until you reach your target measurement.

 

[BadMatrix]

If this is the gauge, with the correct insert, that you are using your are fine. https://www.hornady.com/headspace-bushings#!/ However, the Hornaday base is a POS from a repeatability point of view. If you are using the Hornady OAL gauage it is for bullet seating depth not case headspace. Neck bushing =
https://www.brownells.com/reloading...g-die-parts-accessories/neck-sizing-bushings/ Forget SAAMI spec which is based on a minimum chamber. Get the measurement from a fired case from your gun. If you find it difficult to get to the correct shoulder set-back buy a should bump die. A F/L die and a shoulder bump die take a little finesse but just go slow and adjust your die with minimal movement until you reach your target measurement.

Yeah, the comparator with the anvil. I have one for each caliber I reload. I was talking about a case gauge which I also have for each favorite calibre— https://www.grafs.com/catalog/product/productId/70685

 

[BadMatrix]

I have ONE Swift, a re-barreled 98 Mauser. I used it for a while but decided the very slight advantage it gave over a 22/250 wasn't worth the aggravation of building ammo that worked.

What was the issue you encountered?

 

[AZ10X]

Yeah, the comparator with the anvil. I have one for each caliber I reload. I was talking about a case gauge which I also have for each favorite calibre— https://www.grafs.com/catalog/product/productId/70685

Get a new unfired, un-sized case. Check the length. Seat a bullet short of the lands. If it is hard to chamber and extract you have a carbon throat problem. If not it is your sizing methods. Forget the Wilson case length headspace gauge and forget looking at the SAAMI minimum chamber and cartridge specs. You need to base your sizing on a fired case from your rifle that represents your chamber minus .002 brass spring back. When barrel chambers are reamed they are not an identical match of the mass produced chamber gauges or the SAAMI drawing. When I have a rifle barreled I have the smith ream die blanks with the same reamer used to ream the barrel chamber. This isn't the case with a Ruger factory barrel. There can be quite a bit of plus and minus between the actual factory barrel chamber and mass produced chamber gauges and/or the SAAMI drawings.