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Thread: Firing pin spring pressure in Bat Neuvo

  1. #16
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    Quote Originally Posted by zfastmalibu View Post
    Hi Jackie, I use a lot of these actions. I have about a dozen in the shop now Id guess. They should have about .245" pin fall with no cock on close. Id get a different trigger hanger. Your spring also seems light, from memory the ones I have checked are about 21lb is the cocked position. An excellent ignition design in my opinion. Alex Wheeler
    + one on the ignition system. Instead if the lug style bayonet assembly, it features an interrupted thread. The shroud has a generous diameter fit that allows for perfect alignment.

    I went to the range yesterday, and the Rifle shot great.

  2. #17
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    Quote Originally Posted by jackie schmidt View Post
    + one on the ignition system. Instead if the lug style bayonet assembly, it features an interrupted thread. The shroud has a generous diameter fit that allows for perfect alignment.

    I went to the range yesterday, and the Rifle shot great.
    Jackie- do you feel the changes made a improvement in the way it shot or did it just shoot as good as it did before?

  3. #18
    Join Date
    Apr 2015
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    68

    Bat neuvo

    The BAT NEUVO is a very fine action and should not need any corrections to the ignition system unless
    it is done by Dwight or someone with his knowledge. I would call BAT, Dwight or Chris Harris if you think their
    is a problem. It does not sound like you have started to tune the rifle/action. In my experience, the ignition
    system is very sensitive to any changes(firing pin fall etc.). The rig with a new barrel should be capable of
    shooting sub one groups at 100 yard at a selective seating depth and three different powder loads. I would also review
    the latest info with regard to lighter firing pin weights.

  4. #19
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    Quote Originally Posted by tunermi View Post
    The BAT NEUVO is a very fine action and should not need any corrections to the ignition system unless
    it is done by Dwight or someone with his knowledge. I would call BAT, Dwight or Chris Harris if you think their
    is a problem. It does not sound like you have started to tune the rifle/action. In my experience, the ignition
    system is very sensitive to any changes(firing pin fall etc.). The rig with a new barrel should be capable of
    shooting sub one groups at 100 yard at a selective seating depth and three different powder loads. I would also review
    the latest info with regard to lighter firing pin weights.
    Well, when I took this action to the range the first time, The extractor would not catch one out of every three cases, forcing me to push the case out with a cleaning rod.The Sako extractor was either installed too far back in the bolt body, or the part of the extractor that hooks on the case was too thick. The distance between the inner face of the extractor hook and the bolt face was too tight. I tried dressing the inner face of the extractor hook with small Emory files, but could not get enough off. I finally mounted the extractor in my tool grinder and dressed the inside face to where the extractor had about .003 clearance, allowing it to snap over the case every time. Problem solved.

    Also, Bat knows the primary purpose of this action is a short range Benchrest Rifle. So why does it come with an ejector spring that throws the case 5 feet. That’s not a problem for someone like me, I can remove the ejector and tune the spring to where it pitches the case right next to Rifle on the bench. But for others, it could be a problem if they don’t feel comfortable working on it.

    By the way, after increasing the firing spring pressure, I installed my favorite 6PPC HV barrel and shot the best groups I have shot with the Rifle to date. I then put my 1-12 twist barrel shooting the Bart’s 80 grn on and won the next 200 yard VFS Match at Tomball.

    Also, Bat should offer this action without all of the lightening cut aways and side scalloping on the action body. They are assuming everyone wants this action to build a LV. They could leave the action in it’s round form, increasing stiffness for applications such as a HV or Rail Gun where minimum weight is not much of a factor.

    I am aware this might be prohibitive, since most of these operations are done on a CNC setup.

    All in all, the Bat Neuvo features some of the best innovations in action design we have seen in several decades. I plan on getting another in the near future in drop port.
    Last edited by jackie schmidt; 05-25-2019 at 12:00 AM.

  5. #20
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    Augusta, Maine & Palm Coast, Fl
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    I don't know why

    some folks seem to think others who have professional capabilities should seek permission to do simple alterations to suit their own likes and dislikes. Not everyone is mindless and without mechanical skills. It makes me want to puke sometimes, the things that are said on here. Mindless people are boring. Tinkerers are interesting and what Benchrest use to be all about. I don't know about anyone else but I decided a long time ago I don't have to call the king my uncle if I don't want to.There are a few of us left. If we bust it, by god we'll eat it or fix it.

    Pete
    Last edited by Pete Wass; 05-26-2019 at 09:57 PM.

  6. #21
    Join Date
    Feb 2003
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    199

    Yes - Yes - and YES!

    Quote Originally Posted by jackie schmidt View Post
    5 lbs? I'm not sure that would fire a primer.

    i have cured more than one erratic shooting Rifle by increasing the pin travel and giving it no less than 22 lbs of static pressure. Early Farleys were some of the worst.

    Years ago, a good friend had a brand new Farley Rifle built. The first time he brought it to the range, it was super smooth and slick, you could just flip that bolt open with your finger. Everybody marveled at the workmanship.

    The problem was you could not make two bullets touch. He was convinced the barrel was bad. We took the Rifle to my shop where I offset drilled the trigger hanger and bushed it back for the 1/8 hanger pins. This moved the trigger back to give the firing pin at least .220 inch travel. I then machined a spacer to give it at least 22 lbs of static spring pressure, which will be about 28 pounds in cocked position.

    The first group he fired after these mods was a mid "one", the Rifle suddenly became a real shooter.

    In my opinion, one of the reasons Pandas shoot so well out of the box is Kelbly builds them with a substantial firing pin travel and 23+ pounds of static spring pressure.

    I have fixed quite a few rifles that didn’t shoot by simply increasing the firing pin fall. Most of the rifles in question had fall around 0.210” or less total travel, and 22-23 pound springs.

    About ten years ago or so, I experimented quite a bit with ignition. I used a 6mm PPC and a -0.100” short 22 PPC. I used surplus IMR-8208 in the 6mm and H-4198 in the 22, and Federal 205 (non-match) primers of the same lot number.

    I did the testing with a Stolle Panda/Young rail-gun configured with an 8” long barrel block with a round cavity. Barrels were clamped into the block with two 4” Delrin sleeves. I used a variety of spring weights and adjusted the fall accordingly. The testing was done with a Jewell BR, a Kelbly, and a Shilen BR trigger.

    I also tried three different styles of firing pins. I used a standard 41 gram firing pin, the same style of firing pin with flutes (don’t remember the weight), and a popular “speed firing pin” with a body made from lightweight metal. The fluted firing pin was interestingly enough, an original Remington. I don’t remember what model action it came from. Firing pin tip diameters were 0.067”. Firing pin protrusion with all three samples used was 0.050 to 0.055”.

    Incidentally, the triggers and the firing pin assemblies were tested to ensure they had consistent lock time. This crucial parameter was measured with a fiber-optic/DAQ sensing system that I devised.

    I wore out two good Krieger 6mm unlimited barrels and a Hart 22 unlimited barrel, and wasted countless amounts of really good bullets over a three year period. I say I wasted because I should have known better - and deviating from established standards would only create problems and be a disappointment in the long run.

    In a nutshell, what I found was that fall below 0.230” with a 23 pound spring resulted in inconsistent precision. Under almost every circumstance, 0.250” to 0.280” of fall produced the smallest groups day to day. What made the testing so elusive was that it wasn’t as if short fall preformed poorly every day. Some days, the groups were just as small as they were with long fall. But after months of testing, it becamee quite obvious that short fall (<0.230”) didn’t perform as consistently from day to day. I remember the groups with short fall would often have low vertical or low diagonal shots.

    One thing I found conclusive was spring weight below 20 pounds, or firing pin travel below 0.200”, and/or the lightened firing pins were worthless. Groups when using either-or would be random, and were often times never round in shape.

    One way I quantitively gaged the firing pin inertia was by measuring the penetration of the firing pin into a live primer (no propellant or bullet). I used brass with tight headspace which would close with considerable resistance on a stripped bolt. I don’t have all of the detailed figures of measurements at hand, but I specifically remember that a 41 gram 0.067” firing pin using a 23 pound spring with 0.250” of fall penetrated a Federal 205 primer 0.018-0.020”. I got this idea for penetration measurement from George Sr. Kelbly and Mike Walker. Mike Walker said that ignition testing back in the day was done with specially made copper inserts used in a test fixture, and the amount of penetration should be around 0.020” for reliable ignition. Unfortunately I couldn’t get much detail from him at the time because he was quite difficult to communicate with due to his deafness. So, I surmised that my method would be a close approximation of the standardized testing.

    The shortened fall and lighter firing pin spring weights all reduced the penetration to 0.012” to 0.015”. I also remember widely varying/inconstant amounts of penetration with the lightened firing pins.

    My conclusion from the testing was that springs below 22 pounds and firing pin fall under 0.230” were undesirable. I also remember that a variety of springs would vary in tension depending on how much they were used. I tried springs that were 30 years old with heavy use, yet still had 23-24 pounds of tension, but sometimes new springs degraded below 20 pounds within a few months…or even only after weeks of use.

    Another interesting side note concerned the tightening torque of the screws on the barrel block was very important, especially for long shot strings. If the torque on the (lubricated) screws fell below 60 in/lbs, the rail gun wouldn’t shoot good ten shot groups. It may have shot good three to five shot groups, but not ten shots. The groups would wonder around randomly and get larger if the torque on the block was too low. Also, after several years, I switched to an aluminum sleeve/collet because the Delrin seemed to cold-flow and would eventually move around regardless of the screw torque. I suspect this was worse under extreme temperature changes of the barrel. This is a whole ‘nuther topic in itself!

    Such testing can be ephemeral when shooting out in the conditions. Obviously it would be more meaningful if I could have done this in a tunnel. It could have been that I had to go to extremes of firing pin travel and spring weights to see a subsequent and noticable change on the target.

    Another definitive conclusion during my testing - the bullet had to be "somewhere" into the rifling to shoot well from day to day. Jumping the bullet gave almost as inconsistent results as short firing pin fall.

    Other confounding variables I thought of years later which could drastically change the results (and maybe even invalidate my testing) are types of propellant and the amount of neck tension used. My circumstances required light to medium neck tension with the 22 SPPC and the 6mm PPC...the 22 especially so because H4198 seemed to prefer relatively light neck tension (about 20 lbs. seating pressure).

    It may be that the current trend of using very heavy neck tension can allow for a lighter strike to perform consistently because it would allow the propellant to start the deflagration process before the bullet moves into the rifling. I suspect that the bullets were moving into the rifling under the initial shock of the primer detonation with the light neck tension that I used.

    In conclusion, I wouldn’t recommend deviating too far from established ignition standards.

    Greg Walley
    Abraxas LLC

  7. #22
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    Thumbs up Thank you, Greg and Jackie.

    Great thread!RG

  8. #23
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    Thank you Greg!

  9. #24
    Join Date
    Dec 2006
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    Did some quick measuring on the two Neuvo actions I have. Measured both bolts in the same action, and both had very close to .252" of fall. Spring pressure in cocked position is about 22,5-23lbs.

  10. #25
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    Mar 2012
    Location
    SW Montana
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    Quote Originally Posted by Greg Walley View Post
    I have fixed quite a few rifles that didn’t shoot by simply increasing the firing pin fall. Most of the rifles in question had fall around 0.210” or less total travel, and 22-23 pound springs.

    About ten years ago or so, I experimented quite a bit with ignition. I used a 6mm PPC and a -0.100” short 22 PPC. I used surplus IMR-8208 in the 6mm and H-4198 in the 22, and Federal 205 (non-match) primers of the same lot number.

    I did the testing with a Stolle Panda/Young rail-gun configured with an 8” long barrel block with a round cavity. Barrels were clamped into the block with two 4” Delrin sleeves. I used a variety of spring weights and adjusted the fall accordingly. The testing was done with a Jewell BR, a Kelbly, and a Shilen BR trigger.

    I also tried three different styles of firing pins. I used a standard 41 gram firing pin, the same style of firing pin with flutes (don’t remember the weight), and a popular “speed firing pin” with a body made from lightweight metal. The fluted firing pin was interestingly enough, an original Remington. I don’t remember what model action it came from. Firing pin tip diameters were 0.067”. Firing pin protrusion with all three samples used was 0.050 to 0.055”.

    Incidentally, the triggers and the firing pin assemblies were tested to ensure they had consistent lock time. This crucial parameter was measured with a fiber-optic/DAQ sensing system that I devised.

    I wore out two good Krieger 6mm unlimited barrels and a Hart 22 unlimited barrel, and wasted countless amounts of really good bullets over a three year period. I say I wasted because I should have known better - and deviating from established standards would only create problems and be a disappointment in the long run.

    In a nutshell, what I found was that fall below 0.230” with a 23 pound spring resulted in inconsistent precision. Under almost every circumstance, 0.250” to 0.280” of fall produced the smallest groups day to day. What made the testing so elusive was that it wasn’t as if short fall preformed poorly every day. Some days, the groups were just as small as they were with long fall. But after months of testing, it becamee quite obvious that short fall (<0.230”) didn’t perform as consistently from day to day. I remember the groups with short fall would often have low vertical or low diagonal shots.

    One thing I found conclusive was spring weight below 20 pounds, or firing pin travel below 0.200”, and/or the lightened firing pins were worthless. Groups when using either-or would be random, and were often times never round in shape.

    One way I quantitively gaged the firing pin inertia was by measuring the penetration of the firing pin into a live primer (no propellant or bullet). I used brass with tight headspace which would close with considerable resistance on a stripped bolt. I don’t have all of the detailed figures of measurements at hand, but I specifically remember that a 41 gram 0.067” firing pin using a 23 pound spring with 0.250” of fall penetrated a Federal 205 primer 0.018-0.020”. I got this idea for penetration measurement from George Sr. Kelbly and Mike Walker. Mike Walker said that ignition testing back in the day was done with specially made copper inserts used in a test fixture, and the amount of penetration should be around 0.020” for reliable ignition. Unfortunately I couldn’t get much detail from him at the time because he was quite difficult to communicate with due to his deafness. So, I surmised that my method would be a close approximation of the standardized testing.

    The shortened fall and lighter firing pin spring weights all reduced the penetration to 0.012” to 0.015”. I also remember widely varying/inconstant amounts of penetration with the lightened firing pins.

    My conclusion from the testing was that springs below 22 pounds and firing pin fall under 0.230” were undesirable. I also remember that a variety of springs would vary in tension depending on how much they were used. I tried springs that were 30 years old with heavy use, yet still had 23-24 pounds of tension, but sometimes new springs degraded below 20 pounds within a few months…or even only after weeks of use.

    Another interesting side note concerned the tightening torque of the screws on the barrel block was very important, especially for long shot strings. If the torque on the (lubricated) screws fell below 60 in/lbs, the rail gun wouldn’t shoot good ten shot groups. It may have shot good three to five shot groups, but not ten shots. The groups would wonder around randomly and get larger if the torque on the block was too low. Also, after several years, I switched to an aluminum sleeve/collet because the Delrin seemed to cold-flow and would eventually move around regardless of the screw torque. I suspect this was worse under extreme temperature changes of the barrel. This is a whole ‘nuther topic in itself!

    Such testing can be ephemeral when shooting out in the conditions. Obviously it would be more meaningful if I could have done this in a tunnel. It could have been that I had to go to extremes of firing pin travel and spring weights to see a subsequent and noticable change on the target.

    Another definitive conclusion during my testing - the bullet had to be "somewhere" into the rifling to shoot well from day to day. Jumping the bullet gave almost as inconsistent results as short firing pin fall.

    Other confounding variables I thought of years later which could drastically change the results (and maybe even invalidate my testing) are types of propellant and the amount of neck tension used. My circumstances required light to medium neck tension with the 22 SPPC and the 6mm PPC...the 22 especially so because H4198 seemed to prefer relatively light neck tension (about 20 lbs. seating pressure).

    It may be that the current trend of using very heavy neck tension can allow for a lighter strike to perform consistently because it would allow the propellant to start the deflagration process before the bullet moves into the rifling. I suspect that the bullets were moving into the rifling under the initial shock of the primer detonation with the light neck tension that I used.

    In conclusion, I wouldn’t recommend deviating too far from established ignition standards.

    Greg Walley
    Abraxas LLC
    EXCELLENT post, I agree 100% with your pin fall and spring recommendations. All I can ad I like to see similar minimums along with any firing pin bind corrected which is all too common. Shooters just need to get over the stiffer bolt opening required with a well setup ignition. I also see similar anomalies with some actions that seem to perform with much less ignition energy, but like you said, over the months they are not as consistent. Thanks for the interesting post, Alex
    Last edited by zfastmalibu; 05-27-2019 at 06:45 PM.

  11. #26
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    better and Better and BETTER!!!!


    Thank you Greg for joining this most instructive thread!

  12. #27
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    Jackie, if you want a heavier Neuvo, look at the Neuvo M. It was designed for long range, and is ideal for a drop port BR case in my opinion. Maybe a little more than you need for the ppc case but I dont know that it will slow you down much. The bolt stroke is .9" longer.

  13. #28
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    Quote Originally Posted by zfastmalibu View Post
    Jackie, if you want a heavier Neuvo, look at the Neuvo M. It was designed for long range, and is ideal for a drop port BR case in my opinion. Maybe a little more than you need for the ppc case but I dont know that it will slow you down much. The bolt stroke is .9" longer.
    The long range version appears to be just a longer version of the regular Neuvo with an integral Rail. Same diameter at 1.35 inches.

  14. #29
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    Yes, 1.350 with a flat bottom, integral lug and rail. There have been some tweaks but basically the same action.

  15. #30
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    Great post Greg, missed you at the SS, had rum and chocolate.

    Dan Honert

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