Tubb firing pin in Mod 70?

[DRNewcomb]

I have a post-64 Target Mod 70. I purchased a Tubb SpeedLock firing pin under the impression that I could reuse the original factory cocking piece. Looking at the factory firing pin now, it appears that this was a bad idea, at best, and that I should have bought the cocking piece to go with the pin.

Anyone familiar with these firing pins care to enlighten me?

 

[Alex Wheeler]

If this is a lightweight pin I'd pass on it. Lightweight pins sacrifice ignition energy, add harmonics, increase lift, (if they come with a heavier spring to try and make up for the lost mass) in an attempt to reduce lock time. Are you shooting silhouette? I cant think of any reason to use those pins unless your discipline requires standing shots.

 

[butchlambert]

Listen to Alex,
It will do absolutely nothing for you.

 

[Ggmac]

Do not use it , you will be chasing gremlins !

 

[lloydx2]

If the shaft is threaded, It is intended to be used with his cocking piece
His cocking piece will also be threaded. That way you can adjust pin fall
Once this is done you finish drill the shaft and pin it. The cocking piece
cam finger will also be thicker at the base than a factory one. If you look
up Dave at Superior Shooting Systems he is always ready to help.

 

[DRNewcomb]

Thanks for everyone's comments. I'll probably order Tubb's cocking piece next time I place an order to Brownell's. This will allow me to leave the factory pin alone so that I can easily switch back if the light-weight pin does not help or makes things worse.

 

[RWO]

Using a reduced mass firing pin with the original spring will not reduce energy delivered at primer strike. The total energy is determined by the spring's compression and its spring constant, period. The energy at strike is 1/2MV^2. If M is reduced by going to a light pin, V will increase the exact amount to keep the total energy the same as it was with the original (heavy) pin. This is simple physics and is indisputable.

The increase in V reduces lock time and is the only benefit of using a light pin. If you can bring yourself to bear a little high school math, I suggest you read the Appendix , " Lock Time" in his first book , "The Bolt Action". He explains in easily understood text the ins and outs of firing pin/spring operation, speedlocks, and describes various commercial units.

RWO

 

[butchlambert]

A lot of people have helped our Bats by adding a tungsten weight to the firing pin. What is the message here?

 

[lloydx2]

Better Harmonics?

 

[butchlambert]

Better Harmonics?

Good firing pin strike.

 

[RWO]

A lot of people have helped our Bats by adding a tungsten weight to the firing pin. What is the message here?

Helped how? Show your data.

RWO

 

[butchlambert]

Helped how? Show your data.

RWO

Next time that you are in the neighborhood, I will show you targets.
By the way, send Dwight Scott an email or call him. He is the original accuracy smith to do this and others are also. I would say Dwight is as good as is out there.

 

[dkhunt14]

Using a reduced mass firing pin with the original spring will not reduce energy delivered at primer strike. The total energy is determined by the spring's compression and its spring constant, period. The energy at strike is 1/2MV^2. If M is reduced by going to a light pin, V will increase the exact amount to keep the total energy the same as it was with the original (heavy) pin. This is simple physics and is indisputable.

The increase in V reduces lock time and is the only benefit of using a light pin. If you can bring yourself to bear a little high school math, I suggest you read the Appendix , " Lock Time" in his first book , "The Bolt Action". He explains in easily understood text the ins and outs of firing pin/spring operation, speedlocks, and describes various commercial units.

RWO

This is not true. Dwight Scott proved to Bat his ignition was not great. He was the first to add tungsten carbide weights to firing pins. It makes more consistent ignition. MOST the BR. guys have had theirs redone. Now the new Bats have a heavier pin. What hits harder a BB going 30 mile an hour or a sledge hammer going 15? Matt

 

[dkhunt14]

Helped how? Show your data.

RWO

It made groups smaller. Just ask any short range BR guy. The other year a guy showed up at the shoot at 1000 yards. He shot and i saw what he shot. I came back and asked him what he changed and he said nothing. I said Joe your gun shot way better then that. Then he said he bought a new lightweight firing pin and spring. I told him to take that out and throw it away. He put the old one in and the gun came right back to shooting again. This was on an 80 pound heavy gun. I saw lots of guys try them. If you can see a difference at 100 yards with a PPC it,will show on long distance guns.

If you are shooting offhand it may speed up lock some and help some. But I doubt anyone can hold the few milliseconds of difference. Matt

 

[Alex Wheeler]

Using a reduced mass firing pin with the original spring will not reduce energy delivered at primer strike. The total energy is determined by the spring's compression and its spring constant, period. The energy at strike is 1/2MV^2. If M is reduced by going to a light pin, V will increase the exact amount to keep the total energy the same as it was with the original (heavy) pin. This is simple physics and is indisputable.

The increase in V reduces lock time and is the only benefit of using a light pin. If you can bring yourself to bear a little high school math, I suggest you read the Appendix , " Lock Time" in his first book , "The Bolt Action". He explains in easily understood text the ins and outs of firing pin/spring operation, speedlocks, and describes various commercial units.

RWO

Nope. On paper this is true because the equation is biased towards velocity. But its the same as a 44 mag vs 223. Fast and light vs heavy and slow. Different kinds of energy even if they are the same on paper. Ignition systems are figured out by now and everything said about Dwight is true. There is accuracy in good ignition. Light and fast is not the way.

 

[lloydx2]

I think heavy or light, both ways produce decent energy.
I think it has more to do with harmonics. What is happening
after the pin has fallen

 

[butchlambert]

I think heavy or light, both ways produce decent energy.
I think it has more to do with harmonics. What is happening
after the pin is down.

OK, Why?

 

[lloydx2]

Lighter pin might have a tendency to bounce? More vibration
The heavy pin may transmit less vibration after it stops. I am not sure.
Not many confirmed studies have been conducted. I am not knocking what has
been shown on paper. I just don't see how strike force (fast or slow)
is going to effect primer brisance. The primer either goes or it doesn't.

 

[butchlambert]

Lighter pin might have a tendency to bounce? More vibration
The heavy pin may transmit less vibration after it stops. I am not sure.
Not many confirmed studies have been conducted. I am not knocking what has
been shown on paper. I just don't see how strike force (fast or slow)
is going to effect primer brisance. The primer either goes or it doesn't.

Are you sure about that?

 

[lloydx2]

I not, Than why can you get single digit extreme spreads with a speed lock.