How to improve heavy bolt lift?

[thumper4fun]

This should point you in the right direction. If not, feel free to get with me and I'll walk you through it.

Greg. thanks for the info and the pic. Pin fall is .257

 

[thumper4fun]

The first thing that I would do is to pull the striker assembly and measure the spring weight in cocked position.

Boyd, I have no idea how to do this. Any tips?

You did not mention whether you are the original owner of the rifle or action, and it could be that someone decided to put a heavier spring on yours.

I'm the second owner. Tony Larsen built the rifle in 2011 using a 2011 RBLPRE Panda action. He shot it in a couple matches and decided to retire from point blank shooting shortly after building it. I bought the rifle from him. As far as I know he ordered an off the self action from Kelbly.

The other thing that I would like to know is what the diameter of your firing pin tip is. I have a Viper that came with a 19# cocked spring weight and .200 total fall, that never had any problems, but then it came with a nominal .062 firing pin tip, and they require less spring. I believe that the later Pandas are available with three different tip diameters, depending on what the customer wants.

The firing pin tip measures .067.

 

[BoydAllen]

That would be the middle tip diameter, and IMO a good choice. Notice how Tony opens his bolt. https://www.youtube.com/watch?v=TuyQaVi4mrc
I would still check the cocked spring weight. It may not help, but some time back I mixed a little HBN in some STOS, degreased (wiped off), and regreased the shroud threads and cocking cam, worked the bolt about 20 times, put it away, and the next time that I tried it, it felt really slick. I would not use this on the lugs, because it migrates a little bit.

 

[Erik Cortina]

Best way to find out if there is a problem is to take cocking spring out and reassemble the bolt. Work the firing pin by hand and if there is drag you will feel it. PM me and I might be able to help you out.

 

[RDavies]

I have hear of some shooters having some ignition problems with their Bats which happened to have very light bolt opening. Once they fitted a heavier spring, the ignition improved, but bolt lift got harder.
A while back I fitted a new pin and spring in my Panda and bolt lift got slightly harder but I never had another misfire.

 

[LHSmith]

RDavies- Exactly what I was trying to convey in my previous post. Even Tony Boyer's handling technique includes placing his thumb on the rear tang to minimize bag upset to overcome bolt lift movement. Results on the target would dictate if the problem is perceived or real.

 

[GerryM]

Barrel shank may be too long causing bolt to bind.
when the firing pin in in the bolt everything is tight, take it out and you gain clearance
loosen up the barrel and back it off See what happens

 

[thumper4fun]

Barrel shank may be too long causing bolt to bind.
when the firing pin in in the bolt everything is tight, take it out and you gain clearance
loosen up the barrel and back it off See what happens

Thanks for the suggestion. Completely removed the barrel and the bolt lift was the same with or without the barrel installed.

 

[thumper4fun]

LHSmith & RDavies,

Obviously I don't want to trade one issue for another, improve bolt lift and induce ignition problems. My quest is to improve bolt lift without creating any other issues. Maybe I can, maybe I can't but I won't know until I try.

I do appreciate the heads up. In the end my bolt lift may remain the same and I have to change my handling technique. Either way if it helps me shoot better that's really my end game.

 

[Erik Cortina]

I have two Panda's, ready my suggestion on previous reply and try it. I was able to improve my bolt lift by doing some mods to my bolt.

 

[thumper4fun]

An interesting thing to watch in the video of Tony B shooting. When he is shooting on the sighter target he lifts the bolt with his right thumb on the bolt tang but when he moves to the record target and shoots faster he lifts the bolt with his thumb on the scope.

 

[BoydAllen]

Since I had seen it before, I stopped at the first bolt lift, where he uses the bolt shroud, but you get my point. Sometimes you have to adapt your style to the equipment.

 

[thumper4fun]

Since I had seen it before, I stopped at the first bolt lift, where he uses the bolt shroud, but you get my point. Sometimes you have to adapt your style to the equipment.

Boyd, yes I got your point and it was a good one thanks. I just thought it was strange that Tony B used one technique on the sighter and a different one on the record. Of course he was shooting much faster once he went to the record target.

 

[Rustystud]

First, I will say that Kelbly's has always provided me with first quality service.
They answer the telephone and return their messages.

If the problem is not trash in your bolt, I would check the chamber and brass in the web area for friction restriction. I would check the brass for overall length, and neck diameter. I would check the brass for bulging if you are setting the brass back when reloading.

I have built and re-chambered hundreds of Kelby rifles. If the chambers are to tight you will break extractors every time.

They are made to very strict tolerances, but there are no other actions that are any better at doing what they are designed to do.

As Kelbly's told you send it back to them, or who they recommend. Someone who can systematically trouble shoot the rifle.

Nat Lambeth

 

[GerryM]

Ok so you have the barrel off, the bolt lugs are not galled so there one thing left that I can think of.
That I would look at firing pin spring may be way to stiff.
maybe its a coil or two too long or the wrong one by mistake. you could also compare cam angles with
another Stolle action. Mistakes do happen.

 

[vahena]

Have you checked into Kelblys adjustable trigger hanger to time the trigger, In which it will relieve bolt lift. your may have to play go to bullet central.com or you tube to see how it works. I am not an expert but this seems like the problem the adjustable trigger hanger might fix or a least help relieve the bolt lift. I just order one as my panda rocks in the bags upon bolt lift also, Tubbs springs are another way to go to, also in my search for better bolt lift and still keeping firing pin working without misfires.

 

[dkhunt14]

TUBBS SPRINGS ARE NOT THE ANSWER FOR BR. All the BR shooters I know that tried them took them out. Maybe someone put in a 28 pound or a 32 pound spring. I think pin fall can make them harder. The more fall, the harder to cock. Matt

 

[BoydAllen]

Matt,
When referring to Tubb springs, do you mean the single springs that he has offered for some years, or the dual spring setup that is more recent. I have the latter, and like it. Because the springs are wound in opposite directions, the assembly does not have to rotate slightly against the end of the shroud or firing pin flange as the action is cocked and fired. This removes some of the friction that you feel when cocking the bolt.My Viper has a nominal .062 firing pin tip and for that reason I believe that it can get away with less spring. A friend has them on a couple of Pandas and they seem to work fine for him.
Boyd

 

[dkhunt14]

Boyd I am not sure about the double spring. I know guys tried the regular one and it induced vertical off the bench at 1000 yards. Matt

 

[butchlambert]

Dwight Scott put a tungsten weight in my firing pin and the strike is great. This is on my Bat. Never had a problem with bolt lift on a custom and I have owned many and different brands.