PCP Pistols

Any reason for choosing 6060 over 6061? Lots of skill to thread a pressure vessel tube correctly the grade 8 6mm cap head bolts seem a good option.

Would only run a rifle on co2 without a fal, I'd like to see what a qb78/2250 hybrid could produce with a better designed hammer valve and 80% bore transfer porting with a .25cal barrel, done a lot of research on qb rifles and will transfer that to a hpa target pistol build. Do you think increasing the main tube diameter to 1 1/8" or 1 1/4" for more volume and better flow into the hammer valve to be an improvement Mike? Stock crossman and qb main tube is 7/8" diameter, I know the weights of the hammers so would just modify their dimensions to keep the weight correct or even lighter if needed.

Might start a build thread to put this info in for others that are interested.

Edited by Rusty - 08 Feb 2022 at 12:49pm

i just used 25mm tubing because its close to the origional 2240 tube diameter on guns have built,but it does restrict hpa capacity to approx 50/55 cc evan with 12 inch barrel lengths i normally use for pistols,without regs fitted,depending on power out puts wanted,i can get 12/13 shots from 50 cc in 24fpe range in 22 cal and 4/6 shots in 30/32 fpe range from only 2800psi fill pressures in unreged guns sweet spot with approx 1 fpe over these shot strings.its possible to get significantly higher shot counts from this capacity evan unreged in 12/13 fpe range,depends on what you want and how guns are set up for,i build mostly hunting guns in pistols so want decent power levels,am currebtly building 2x 177 cal target pistols one for bulk co2 the other for hpa,dont plan on reging the pcp at this stage as want to find out how consistant can get velocitys first before decide bout reging it,both pistols will be setup in the 6/8 fpe range,the other reason i use the smaller diameter tubing for pistols is to keep weight and bulk down and because i like the look of the smaller tubing better with pistols,i do have a partly built 30 cal pistol here i used larger 32mm tubing for simply becauase 30 cal uses lot more air,as for the grade alli tubing i use,any those grades with at lest 2,5mm wall thicknes will hold well over 4000 psi saffely proven by lab tests in USA and my tests by myself and others as well,as you said threading for pressure vessels a tricky and very precise job particually using alli but not neccessary up to over 3500 psi,but the machine screw method just dont look as nice i will admit but lot easier to do,hydrolic steel tubing can hold up to 10000psi as many machines today run at this pressure in hydo systems,have seen hpa cylanders on utube made from motor bike front fork cylanders as well,small diameter steel and alli tubing is lot stronger than many think,read somewhere that crosman tests their co2 guns tubing to 3500psi,dont take that as gospel but its proberly correct,think about it the hipacs are just screwed into 2240 co2 tubing and run at 3000psi which means the tubing in front of the hipac is holding 3000psi quite happily.dosnt pay to take these pressures lightly of course they could kill or blow of body bits if got wrong very easily too.Pual you know why i dont post anything bout projects but i am allso bit reluctent to doso the way things are in NZ these days.

Thanks for the info on your builds, I get what you mean being reluctant to post builds on the forum now.. what happend to the NZ we useto enjoy and there's a big difference between an engineer building an airgun and someone thinking they can copy a build thread, liability too 3000psi can be lethal to someone that doesn't understand strength of material eng calcs.

My builds will take a while, still have a zx45 milling machine in pieces getting improvement mods, will start making a few parts on the lathe but the breech block and hammer valve will need mill work done.

Target/hunting pistol design will be the focus hence using hpa over ço2, wouldn't even shoot a bird with my stock 2250 not a humane thing to do if you value a clean kill when dispatching pest. My stoger x20 aint even that effective at shooting pests and its anoying we don't still have the use of .25 and .30 cal pcp rifles for pest control without the hassle of police and their fal control.

I agree Paul - on a custom piece its nice to see how its assembled - screws and all. Shows the thought process and if they are nicely fitting it adds to the quality and craftsmanship! 

Perfectly valid reasons Mike, think most people with a FAL are trying to do nothing that would put their license at risk. Funny that pcp airguns are limited to subsonic speeds so it takes an expensive rifle and high pressures to match equivalent firearms fpe, .25cal pcp can match a .22lr but at a much higher cost.

No pcp build threads on here might be a good idea, there are other forums to look at for that info..

Mike do you cast your own ammo for your builds, I noticed most websites and all nz sites are sold out of .30cal jsb pellets, could only buy .25cal jsb pellets.. here's some useful pics since you have the skills also to figure out the rest. USA made Noe pellet molds are good but usps aint shipping to nz anymore so we kiwis have to be resourceful.

250_BBT_16in_twist.jpg

Cherry_51gr_bbt_.250_cal.jpg

308_cal_BBT_152_gr_zps0blk15f4.jpg

Edited by Rusty - 16 Feb 2022 at 5:33pm

Well thats way more than a few bullets, think their will be more reloading now with this ammo shortage.

I've just got some new roofing lead flashing offcuts and 50/50 lead solder bar to learn to cast by hand, will be making my own molds and just have to run a pellet through my .25 cal barrel to find out the groove and land diameter to size the cutting tool +0.001 over groove diameter. 40 bucks for 150 .30cal pellets id cast my own if NOE makes a run of their hunter pellet molds again its modeled off the jsb pellet.

airgun projectiles are normally made from pure lead,tin makes the alloy bit harder but in the right quantitys easier to cast in moulds,adding tin to alloys for swaging requires a lot more pressure to swage the bullet,big difference between bullets for firearms than bullets for airguns,bullets for firearms need to be lubed to prevent them leading up the barrel badly,and noramlly harder to better resist the significantly higher pressures and stresses put on bullets in firearms,purpose of lubing bullets for firearms is to help reduce the bullets leading up barrel,airgun bullets dont need lubing which is normally caused by the heat from gunpowder partually melting the base of the bullet,and leaving that residue in barrel,this can be reduced by copper gas checks on the base of harder lead bullets in firearms,it is possible to fire hard lead bullets in firearms up to 3000fps if bullets are wrapped with teflon tape with good accuracy,but normally lead bullets in firearms are best kept to no more than 2500fps max,unlubed soft lead as used in airguns wont significantly leave lead residue in barrel,but residue will build up slowly over time in airguns and needs to be removed to maintain accuracy,unlubed soft lead bullets can work extremely well in high powered pcp airguns at velocitys in the 1000/1500fps range,its possible to drive airgun bullets up to higher velocitys with good accuracy as well but generally to gain more energy in airguns bullet weights and calibers are increased and veloctys kept below 1200 fps,good source og info on shooting soft lead bullets in pcp airuns can be found on utube on US varmunt shooting posts and forums,these guys know what they are doing and talking about and are normally using calibers in the 25/30/35 range with decent weight projectiles at quite high velocitys in US made rifles some using nitrogen rather than hpa as nitrogen produces higher velocitys due to being thinner than air higher volumes can pass thru valve and is more free flowing than hpa,i believe swaging soft pure lead bullets produces the best bullets for airguns,as casting soft pure lead is more difficult to get good clean consistant weight bullets than swagind can,i can get swaged soft lead bullets to stay within 1/10 of a grain in weight,its not possible to cast pure lead bullets to that same consistancy.interesting topic.

the only prob with lead head nails is the alloy not very consistant,and they allso often contain a % of antiminy,this metal is what makes lead harder and allso allows lead to be heat treated harder again,i personally wouldnt use lead head nails to produce airgun pellets or bullets unless alloyed in very small quantiys with pure lead  because antinimy will lead the barrel with unlubed airgun ammo,as airgun barrels are normally softer than firearms barrels they are easier to damage getting the lead out of the bore,you can use a bronze brush in firearms but doso to an airgun barrel will likely destroy the barrel.