Different degrees of bolt lift.

[Benjaminrusso89]

It seems like 60 and 90 is the most common of bolt lift/throw degrees. What are the pros and cons of both for hunting and target shooting? Some guys say 60 degree could give you light primer strikes but that was on forums that were posted 10+ years ago so I wonder if technology has changed since then or not. Interested to see what you guys have to say.

 

[patriot07]

Less bolt lift makes it easier to cycle the action quicker and gives you more clearance for your scope. I don't think there is any significant relationship between degrees of bolt lift and firing pin operation.

 

[308pirate]

Some guys say 60 degree could give you light primer strikes but that was on forums that were posted 10+ years ago so I wonder if technology has changed since then or not.

There's no reason for "technology" to change. Sako has been making rifles with 60 degrees of bolt lift since long before 10 years ago and they are as reliable as any rifle with a 90 deg bolt lift.

I know my Sako 75 never failed to fire even when hunting in cold ass weather. I think it's an understatement to say that there's a lot of incorrect information on the internet.

Personally I never found a practical difference in reloading speed between the two.

 

[308pirate]

I don't think there is any significant relationship between degrees of bolt lift and firing pin operation.

The firing pin spring is compressed during cocking. Cocking that takes place over 60 degrees of rotation takes more force (spring rate x compression distance) per degree of rotation than it would if cocking took place over 90 degrees.

One way of mitigating that increase in cocking force is to reduce spring rate, which means there's less energy stored in the compressed spring. This can lead to light primer strikes if done wrong.

 

[dannySH]

I can't talk about 60 degrees but I have 4 Tikkas that have a 70 degrees bolt lift and between all of them I've probably shot 12000 rounds. Never had a single light primer strike.

 

[patriot07]

The firing pin spring is compressed during cocking. Cocking that takes place over 60 degrees of rotation takes more force (spring rate x compression distance) per degree of rotation than it would if cocking took place over 90 degrees.

One way of mitigating that increase in cocking force is to reduce spring rate, which means there's less energy stored in the compressed spring. This can lead to light primer strikes if done wrong.

I understand that part of it, but this is another one of those "theoretical" problems. I don't think there is any manufacturer who would design an action and trade-off bolt throw for an increased possibility of light primer strikes. You design an action with the bolt throw you want and then design the ramp/spring/pin system so that it will function properly.

 

[308pirate]

I understand that part of it, but this is another one of those "theoretical" problems. I don't think there is any manufacturer who would design an action and trade-off bolt throw for an increased possibility of light primer strikes. You design an action with the bolt throw you want and then design the ramp/spring/pin system so that it will function properly.

You asked HOW one could affect the other, THERE is the explanation.

 

[patriot07]

You asked HOW one could affect the other, THERE is the explanation.

Fair enough. I should have qualified that with "in reality". I do think that's only an issue in theory.