TEXAN .458 on 2,200psi

[shortshell]

After trying many hundreds of balls & slugs from a 3,000psi tethered setup I have found the best accuracy I get from 50m to 100m is when the tank pressure is around 2,200 psi. I am only looking for maximum accuracy without going to a higher pressure 4,000psi system. I am only interested in silhouette shooting & at this pressure 350gn lubed lead will knock over 200m steel but at the moment it takes many shots to get a hit. I do not wildly turn the power wheel but up near full hammer spring tension seems to work best for my use. I am going to fit a 2,200 psi regulator to my scuba tank & continue testing. Do any other Texan owners get better accuracy from a lower pressure. As a side note even round balls work more accurately at 50m from only 1,500 to 1,800 psi. I remember the Louis & Clark expedition airgun was only using around 900psi & they only had a hand pump to fill its tank. Also the Austrian Army in the early 1800's used similar big bore airguns until a soldier killed one of Napoleons officers & he decreed that anyone found with such weapons were to be hung. They used a horse driven compressor to fill multiple removable shoulder stock air tanks for 20 ball magazine airguns & soldiers carried a spare tank.

[rsterne]

I do not wildly turn the power wheel but up near full hammer spring tension seems to work best for my use.

Please explain.... full hammer spring tension occurs at maximum power wheel setting.... I would think that at only 2200 psi you would be using near minimum power wheel setting, and hence minimal hammer spring tension.... 

Bob

[shortshell]

When in ones mid 70's one can forget when typing. Sorry I got mixed up as I just looked at the power wheel & it is almost 1/2 way so is on the light side now. I had meant to write minimum spring tension & when you questioned me I remembered I had measured the main spring a while ago & it had softened & lost just over 8mm from when I bought it. I have a new spring on order. I heard that some springs lost some tension so I must have got one of those. Down here mail costs as much as the spring but I could not get a suitable stock spring from local spring makers & having one made was more than twice the price with a long wait time. Covid has slowed things down. Sorry about the mix up.

[Greg_E]

Regulating a big bottle will probably be easier than installing a regulator in the gun, and give you a big plenum.

[rsterne]

I agree, installing a regulator in the gun is a poor idea on a large caliber PCP because you won't have sufficient plenum.... the loss of power would be considerable.... If you are shooting from the bench, just get a regulator for your bottle, and then run the gun tethered to it....

Bob

[Chickenthief]

Altaros makes a dandy little thing that wont put you in the poor house!



https://www.altaros.cz/en/airforce/89-external-airgun-regulator.html

[shortshell]

I had earlier ordered the same unit & will post how it goes at 2,200 psi. Having the texan bottle staying at that pressure gives the best volume as there is no restriction to flow & the regulator has time to replace pressure. I think 2,200 psi is the maximum for that unit.
A while ago I changed scopes & found accuracy got better so I checked the old scope & it had a wandering cross hair. The small fine brass adjusting screws were worn from constantly adjustment especially the elevation one. I purchased a Cold Shot elevation scope mount (not cheap) so once zeroed in for 50m it is the only sight adjustment I use as I always hold off for windage now. It is a lot easier to now adjust for different ranges & so much quicker to zero back to 50m. Over the years I have found the scope screw of many scopes have this wear problem & in my case over 50+ years of lead bullet big bore .458 powder burning shooting as they have similar bullet flight arcs at long range.

[Chickenthief]

I had earlier ordered the same unit & will post how it goes at 2,200 psi. Having the texan bottle staying at that pressure gives the best volume as there is no restriction to flow & the regulator has time to replace pressure. I think 2,200 psi is the maximum for that unit.
A while ago I changed scopes & found accuracy got better so I checked the old scope & it had a wandering cross hair. The small fine brass adjusting screws were worn from constantly adjustment especially the elevation one. I purchased a Cold Shot elevation scope mount (not cheap) so once zeroed in for 50m it is the only sight adjustment I use as I always hold off for windage now. It is a lot easier to now adjust for different ranges & so much quicker to zero back to 50m. Over the years I have found the scope screw of many scopes have this wear problem & in my case over 50+ years of lead bullet big bore .458 powder burning shooting as they have similar bullet flight arcs at long range.

Nah!
I have run one of mine set at 3625psi for the past two years. It feeds my Texan 50 from a CF bottle at 330bar~4875psi without issues.
They state max. at 210bar~3050psi but is does way more than that.

[cosmic]

 Did you have to change the stacking of the Bellville washers or change them for heavier ones ?

[Chickenthief]

Nah mate, it's a nylon screw (on the inlet side) that you turn either way.

Takes 3-5 tries and you'll be within 50psi.
The pressure gauge rotates on the regulator and you can rotate it freely when the regulator is'nt pressurised.

PS. I mark my regulators with a line using an Xacto knife, that way i always know where "zero" is.