GTA
All Springer/NP/PCP Air Gun Discussion General => American/U.S. Air Gun Gates => Crosman-Benjamin Air Gun Gate => Topic started by: brewbear on May 06, 2021, 08:27:43 PM
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Hi all,
I'm just starting on the "air gun path" and I'm curious, does a fluted hammer make a difference (if any) or is is something superfluous.
I've been watching video on you tube and I think I can manage most of the upgrades but why would you want a stronger/weaker hammer spring, a fluted hammer and/or a flat top valve? Please excuse my ignorance here, just wanting to learn from the experienced shooters/tuners.
Many thanks,
Ted
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Stronger/weaker hammer spring - changes the striking force on the valve stem, and therefore the amount of valve opening and time the valve is open.
Fluted hammer - decreases the effect of dead air in the tube to hammer strike.
Flat-top piston - seals a bit more effectively, and decreases the headspace between the piston and the valve body, and therefore increases potential pressure buildup into the valve.
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also keep in mind it all depends on what you are trying to achieve with the gun? do you want it to have more power, smoother action, or are you happy with how it performs and just want to improve it as is, or maybe you just want to have fun doing a build that is unique to you? are you on a budget? these mods can add up and you could easily end up putting a few hundred in upgrades in a $70 gun. im not trying to discourage you, just trying to get you to consider what it is you actually want to do and plan accordingly before jumping in head first. ;)
there are many things you can do DIY by taking it apart and removing burr in machined areas, the trigger and sear, some polishing here and there and all of these things will improve its function without costing much more than some time. do some research, study the EVP, ask many questions. there are a lot of people here who can help you. ;D
the best mod is the long steel breech and most all would agree. but, you lose the stock rear sight and have to buy a sight that works with it like a williams or a MIM sight. what it does give you is a solid platform with a dovetail for scope mounting and a stronger hold on the barrel.
here are a couple threads to give you an idea...
https://www.gatewaytoairguns.org/GTA/index.php?topic=138633 (https://www.gatewaytoairguns.org/GTA/index.php?topic=138633)
https://www.gatewaytoairguns.org/GTA/index.php?PHPSESSID=e954948fe94de2ab9cf24294ace04a00&topic=159203.0 (https://www.gatewaytoairguns.org/GTA/index.php?PHPSESSID=e954948fe94de2ab9cf24294ace04a00&topic=159203.0)
here is a thread i started and many people chimed in to help me with my newest 1377 build. maybe some of their advice will help you as well? ;)
https://www.gatewaytoairguns.org/GTA/index.php?topic=185793.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=185793.0)
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also keep in mind it all depends on what you are trying to achieve with the gun? do you want it to have more power, smoother action, or are you happy with how it performs and just want to improve it as is, or maybe you just want to have fun doing a build that is unique to you? are you on a budget? these mods can add up and you could easily end up putting a few hundred in upgrades in a $70 gun. im not trying to discourage you, just trying to get you to consider what it is you actually want to do and plan accordingly before jumping in head first. ;)
there are many things you can do DIY by taking it apart and removing burr in machined areas, the trigger and sear, some polishing here and there and all of these things will improve its function without costing much more than some time. do some research, study the EVP, ask many questions. there are a lot of people here who can help you. ;D
the best mod is the long steel breech and most all would agree. but, you lose the stock rear sight and have to buy a sight that works with it like a williams or a MIM sight. what it does give you is a solid platform with a dovetail for scope mounting and a stronger hold on the barrel.
here are a couple threads to give you an idea...
https://www.gatewaytoairguns.org/GTA/index.php?topic=138633 (https://www.gatewaytoairguns.org/GTA/index.php?topic=138633)
https://www.gatewaytoairguns.org/GTA/index.php?PHPSESSID=e954948fe94de2ab9cf24294ace04a00&topic=159203.0 (https://www.gatewaytoairguns.org/GTA/index.php?PHPSESSID=e954948fe94de2ab9cf24294ace04a00&topic=159203.0)
here is a thread i started and many people chimed in to help me with my newest 1377 build. maybe some of their advice will help you as well? ;)
https://www.gatewaytoairguns.org/GTA/index.php?topic=185793.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=185793.0)
I believed (wrongly) that after I got my post grad degrees I would be done with reading tons upon tons of research!
I am still reading an inordinate number of articles and research papers - work related. The links you so kindly provided are a much more enjoyable read, they relate to my new hobby, so thank you.
I am waiting for the steel breach and the 14.5" Lothar barrel from Alliance Hobby, they were out of stock for the last couple of weeks. Since I am also about to start casting my own pellets, I need a bit more power and the breech/longer barrel should provide some along with improved accuracy though the pistol/carabine (it has the shoulder stock) is pretty accurate as is. I'm just trying to understand if a fluted hammer along with the Alliance Hobby Flat Man's Pack will get me to the increased power without the need of me having to pump 20 times. I don't plan on doing more than ten pumps and my targets are set at 20, 30 and 40 yards respectively. I already have a reflex red dot mounted so the lack of a rear sight is not a detractor.
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from what i understand, adding flats spots to the side of the hammer increases efficiency of the hammer by reducing drag/friction. makes sense... reducing contact would definitely achieve both. i did my newest 1377 build with this and i like it a lot. i am re-doing my previous 1322 and 1377 builds and both will have this.
i have never actually considered the FTP from Alliance, but it is a very nice design with the "made to fit" without adjustments to the piston and the aluminum design for both sections. you will have to post your experience with it once you install and use it. I use the Mellon Air setup which is about half the price of the Alliance setup and uses a derlin adjustable piston. it is very nice as well.
with power, the flat top setup will give you extra power. typically, most say 7 pumps with an FTP is about equal to 10 pumps with the standard OEM setup. pumping is much easier as well. keep in mind that with the Lothar Walther barrels, they are choked. you will lose about 20 FPS with the choking in trade for much better accuracy. still, my newest 1377 build at 10 pumps is averaging 636 FPS. im in the process of re-doing my 1322 now with the same setup as my 1377, so dont yet know how well it will do FPS wise? a week or two yet before it will be ready (waiting on parts) to test on the Chrony.
with the "max Flow" transfer port. what i learned recently here is that it is only of any value if you port the barrel to match the wider ID of the TP and really only beneficial on .22 calibers or higher. if both dont match, it creates a choke point for the air as it passes from the TP through the port of the barrel. according to a chart that Wyoman sent me... the stock TP at .140 ID, the 1322 is good for to just above 450 FPS. if you port the barrel to match the max flow TP (.156 ID), you will be just above 550 FPS. now, this all depends on what weight of pellet you use too, so it could be more or less. ;)
i have the max flow TP's but after learning the above... i am going back to the stock TP's. my tools are crude by machining standards, and i can do it, but the spare barrel i tried this on left me with concerns. enough so that i dont want to risk damaging the LW barrels on the actual guns. maybe down the road? i want to see what i get with the stock TP before i revisit that option.
the stronger hammer spring is beneficial with higher pumps, above 10 and with using the FTP setup. you can only pump so many times before the hammer cant force the valve to stay open long enough to dump all the air in the valve on a single shot. this results in a weaker second shot. you will know once you have your build ready to test. pump it 20 times, unloaded of course, cock it and pull the trigger. cock it a second time and pull the trigger. if your valve is retaining air... you will know it. some use stronger springs, some use power adjusters. i use both. the truth is i dont need too as the stronger spring alone is enough to dump all the air at 20 pumps in my 1377 but i will leave it installed. i never need to go above 10 pumps either, 5-7 is my norm at 25 yards... but it is nice to have the option. ;)
the one thing i would definitely recommend is the deburring. until this new build, i never really imagined just how much of a difference it could make? it is smoother and i can feel the difference. it is also important particularly in the pump handle area where burr can damage the piston o-ring, and the valve o-ring when you install it. it does take additional time to do, but i can tell you that it is well worth it. ;)
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Thank you for your insights. As I am ordering the kit from Alliance, I will ask him to match the barrel port to the TP since we're still waiting for the barrels. Thank you for letting me know.
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Modifying a stock Crosman hammer with flutes is not the easiest job in the world, you can't easily do it with a ball mill, because the hammer is case hardened.... You can grind slots in the sides with the corner of a grinding wheel, but it will look exactly like that is what you did when you are finished.... That is why most who want to reduce the area in contact with the inside of the tube just grind flats on the side.... In addition, flats will remove less weight, which may be good or bad, depending on the results you want....
Bob
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Modifying a stock Crosman hammer with flutes is not the easiest job in the world, you can't easily do it with a ball mill, because the hammer is case hardened.... You can grind slots in the sides with the corner of a grinding wheel, but it will look exactly like that is what you did when you are finished.... That is why most who want to reduce the area in contact with the inside of the tube just grind flats on the side.... In addition, flats will remove less weight, which may be good or bad, depending on the results you want....
Bob
Thank you for the cautionary words, we'll see what comes out of my planned modifications. I didn't plan on modifying the hammer myself for two reasons: I barely have enough time to shoot my targets about 30 minutes every other day and I don't think I have the skills to do a very good job of it. I opted to order a fluted hammer on e-bay, I'll get back here and let you know how it comes along.
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Thank you for your insights. As I am ordering the kit from Alliance, I will ask him to match the barrel port to the TP since we're still waiting for the barrels. Thank you for letting me know.
i would be curious to know if he agrees to do the barrel porting and how much extra he charges you? might be an option i may follow you on? ;)