Heavy bolt lift...what am I missing?

[RichMoAK]

On my 6br, I have heavy bolt lift on MOST cases, but not all (all cases were of the same lot). About 30% of them never give a problem with bolt lift.

-I'm not overpressure. Middle of the chart powder weights. No ejector marks. No flattened primers.
-I'm not oversized. Consistent should bump .002-.003. Verified with Wilson case length mic/case gauge...every time I size.
Case trim length set with Henderson trimmer.
-I'm not under-annealed. I anneal with the AMP
-10x fired, Lapua brass
-bullet seating is .025 off the lands

I've read everything I can on "clickers" and heavy bolt lift I can find. I bought a Small Base, FL, type S sizer to replace my non-SB die to make sure the case web was getting sized down. This helped but did not consistently fix the heavy bolt lift.

I then bought a RCBS 1" vernier micrometer to try and tell which cases were hard to open and which ones weren't. The weird thing was that the smaller cases were HARDER to lift the bolt than the larger cases were.
Here's some measurements:
These were the easy bolt lift cases measured with the vernier mic at the .200 line on the case web: (pre-sized)
.4711, .4710, .4711

These were the heavy lift cases: (pre-sized)
.4708, .4710, .4707

Even more astonishing was when I fired virgin brass in a side-by-side test one day against these 10x fired. These were moderately hard to open as well...

What am I missing?
Why are the smaller dimension cases harder to bolt lift?

 

[CNC-Dude]

Have you tried to rechamber the brass that's been fired that is tight...? Mark it up with a Sharpie to see if that helps reveal anything.

 

[rijndael]

Is the bolt lift hard with no brass, where you've dropped the pin on an empty chamber? If so, is your cocking piece/ramp lubed?
(the part where the cocking piece rides in the cutout on the bolt body)

 

[SeabeeKen]

Assuming the brass length is within spec, Im leaning towards a rifle issue of some sort but I've been wrong before. I've had clickers in the past but the bolt lift was normal until the bolt handle got near the top of the stroke.

 

[RichMoAK]

Have you tried to rechamber the brass that's been fired that is tight...? Mark it up with a Sharpie to see if that helps reveal anything.

I'll try this.

 

[RichMoAK]

Is the bolt lift hard with no brass, where you've dropped the pin on an empty chamber? If so, is your cocking piece/ramp lubed?
(the part where the cocking piece rides in the cutout on the bolt body)

No, it's as smooth as glass. This was one of the first solutions I tried. Thanks!

 

[RichMoAK]

Assuming the brass length is within spec, Im leaning towards a rifle issue of some sort but I've been wrong before. I've had clickers in the past but the bolt lift was normal until the bolt handle got near the top of the stroke.

Only on SOME of the brass is it difficult from the very start of the upstroke. I've done everything I know to get and keep the brass in spec. Thanks!

 

[No manches"]

What brand of action is this?
Remington 700 have this problem, bolt cam timing issue....
Also some savage's are known to do this

 

[ChrisNZ]

Well many of the last 700s had -no- primary extraction but this is not the same necessarily as "hard bolt lift"

 

[RichMoAK]

What brand of action is this?
Remington 700 have this problem, bolt cam timing issue....
Also some savage's are known to do this

This is a TL3 Bighorn.
Wouldn't this effect all cases and not just some?

 

[Roughrice]

I had a similar situation on a new Rem 700 rifle... snug bolt closing.
I bumped back shoulder enough to close easily. After firing... snug bolt lift again.
After a couple of firing sessions during load development... Boom! Case head separation!
Confused, I looked over the case head and noticed the concaved case head shape.
Took it to a smith and... YEP!... Convexed (bulging) bolt face.
This condition made it tight to close by pushing against outer primer cup rim, thus thought needing shoulder bump. This caused light touch only on primer area when closed. Then, when fired...slammed the casehead rearward and stressing case due to an excessive headspace issue.

Problem solved: Smith re-faced bolt... which ended up only cutting .003-.004 bulge off center to square.
Headspace was corrected and alleviated all problems with tight bolt and brass issues.

Just my odd situation.

 

[Ggmac]

On my 6br, I have heavy bolt lift on MOST cases, but not all (all cases were of the same lot). About 30% of them never give a problem with bolt lift.

-I'm not overpressure. Middle of the chart powder weights. No ejector marks. No flattened primers.
-I'm not oversized. Consistent should bump .002-.003. Verified with Wilson case length mic/case gauge...every time I size.
Case trim length set with Henderson trimmer.
-I'm not under-annealed. I anneal with the AMP
-10x fired, Lapua brass
-bullet seating is .025 off the lands

I've read everything I can on "clickers" and heavy bolt lift I can find. I bought a Small Base, FL, type S sizer to replace my non-SB die to make sure the case web was getting sized down. This helped but did not consistently fix the heavy bolt lift.

I then bought a RCBS 1" vernier micrometer to try and tell which cases were hard to open and which ones weren't. The weird thing was that the smaller cases were HARDER to lift the bolt than the larger cases were.
Here's some measurements:
These were the easy bolt lift cases measured with the vernier mic at the .200 line on the case web: (pre-sized)
.4711, .4710, .4711

These were the heavy lift cases: (pre-sized)
.4708, .4710, .4707

Even more astonishing was when I fired virgin brass in a side-by-side test one day against these 10x fired. These were moderately hard to open as well...

What am I missing?
Why are the smaller dimension cases harder to bolt lift?

POSSIBLE, the smaller cases do NOT have enough cling to chamber walls . Just a guess . How is your chamber finished ? Another possibility is that some cases have oil or water on them , alowing them to exert more bolt thrust . Again just a guess

 

[cheek9075]

I had a 22 Beggs do this. Chamber at the web to to small. Ran a different reamer in it and all was good. Only about .002-.003 inch difference in the 2 reamers..

 

[clowdis]

Do you have a 6BR Remington chamber or 6BR Norma?

 

[K22]

Are there any "wear marks" on the cases which might indicate a rough chamber. I had a Weatherby Vanguard with a similar problem. Some case extracted without issue with an easy bolt lift, others exhibited difficult bolt lift and extraction.

The smith immediately found the problem, rough chamber. He polished the chamber and no more problem. The affected case did show wear marks. I can't answer why it didn't affect all cases because like you, the cases were new, same lot and dedicated only to that rifle. But some worked fine, others didn't until he polished the chamber.

 

[MislMan]

You stated hard bolt lift with reloaded brass as well as new brass/ammo. I figure it has to be a rifle issue and I‘m thinking it has something to do with the firing pin itself (lube or bent). Maybe trigger to bolt (trigger reset Or timing).

 

[RichMoAK]

Do you have a 6BR Remington chamber or 6BR Norma?

Norma

 

[Dusty Stevens]

You need a better die, better fitted to your chamber i should say. Also like was said above you may have a poorly finished chamber

 

[Mike Casselton]

What is your neck clearance?
Does a bullet drop into a fired case that hasn't been resized.

 

[338 dude]

On my 6br, I have heavy bolt lift on MOST cases, but not all (all cases were of the same lot). About 30% of them never give a problem with bolt lift.

-I'm not overpressure. Middle of the chart powder weights. No ejector marks. No flattened primers.
-I'm not oversized. Consistent should bump .002-.003. Verified with Wilson case length mic/case gauge...every time I size.
Case trim length set with Henderson trimmer.
-I'm not under-annealed. I anneal with the AMP
-10x fired, Lapua brass
-bullet seating is .025 off the lands

I've read everything I can on "clickers" and heavy bolt lift I can find. I bought a Small Base, FL, type S sizer to replace my non-SB die to make sure the case web was getting sized down. This helped but did not consistently fix the heavy bolt lift.

I then bought a RCBS 1" vernier micrometer to try and tell which cases were hard to open and which ones weren't. The weird thing was that the smaller cases were HARDER to lift the bolt than the larger cases were.
Here's some measurements:
These were the easy bolt lift cases measured with the vernier mic at the .200 line on the case web: (pre-sized)
.4711, .4710, .4711

These were the heavy lift cases: (pre-sized)
.4708, .4710, .4707

Even more astonishing was when I fired virgin brass in a side-by-side test one day against these 10x fired. These were moderately hard to open as well...

What am I missing?
Why are the smaller dimension cases harder to bolt lift?

, color with black sharpie and chamber , look for rubs or contact