OK - I've now been playing around with fitting the data and comparing the resulting equations for 3rd, 4th, and 5th power polynomials for several days, and have learned a lot. I do think I need to get some longer trace data to work with, as all I have so far that is "good" has the first point picked up a little less than 7 yards out, and ends at the target at about 42 yards out. I do have several shots of this data, but would like to see what I get with much more distance - but I don't reguallry shoot beyond 55 yards so it would not be much longer.

The short answer I can give is that al three do a very good of creating a usable "smoothing" equation for the range of good data, but I trust none of them for forecasting the results for more than a few yards outside the range of data that was used to create the equation. Additionally, how good that forecast is will depend on the results of each individual shot, but in general I would trust the 3rd order fit better than the other two - they can get wacky really fast, at least with the data that I have on hand to work with.

To illustrate the fit, I'll show four plots. All four show the results of each equation plotted for speed against distance, and the plots run from zero to 50 yards, but have grey boxes covering the first 6.5 yards and last 8 yards, as these ranges do not have any usable data from the Lab Radar for creating the equations.

The first three plots all use the same shot data, but vary the amount of the data used to create the equations. Plot 4 shows a different shot:
- Plot 1 uses all data from shots ranging from 7 to 42 yards (63 data points),
- Plot 2 uses data only from shots ranging from 15 to 35 yards (36 data points) - the other points are all "forecasts" for speed
- Plot 3 uses data only from shots ranging from 18 to 32 yards (25 data points) - same as above, and is illustrative of how fast things can fall off
- Plot 4 is the same data range as Plot 3, but show the results form a different shot (thus looks a good bit different).

In the original post, and later update to GA BC values, I used the forecasted speeds from 0 and 50 yards. When I recalculate them using 7 and 42 yard smoothed data (staying fully inside the range of data used for the equations) I get the following list of BCs for the five shots:
0.0307, 0.0355, 0.0352, 0.0355, and 0.0343 - this gives a spread of 0.0048 in BC values, for a bit over 13% of variation, so the original point still holds for this data.

It has been fun learning through this, and I'll learn much more going forward. Interestingly, none of the three really match what the Lab Radar says for muzzle velocity that well - sometimes the 3rd order is better, and sometimes the 4th order is better. I'll have to do more testing on that.

A mini lathe and I know nothing about machining.

A.G.R said:

I’ve wondered myself about the gas ram 250. Trigger is my concern

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I think they are kinda like the Cometa. I don't know first hand. You know a lot more about triggers than I do. I just jerk on them.

Things could be worse for sure. The Cometa works great. You learn a bit different trigger pull. I have no complaints. I can shoot dime size patterns at 25 off my knees with iron sights. So the trigger isn't holding me back much.

Of course I've heard the horror stories about them. If I get a bad one I'll deal with it then. So far so good.

I'd like to shoot a "two fifty" before I spent my two fifty. Thats probably not going to happen.

Emu said:

Have you solved the problem?

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Apologies for the late reply but yes, I took the valve to bits and sprayed it with brake cleaner. It must have had some dust or something in there, possibly bits of o-ring as the rifle had a burr on the filler hole which was eating o-rings.

Some of the guys over at www.gatewaytoairguns.com are really into the older stuff. There's a vintage section there that probably has an answer for you.

Cheers,

J~

PIcs of the sticker on the back i will mail to H&N shortly.



And allow me to premature on behalf of my M8 to say Danke sehr for the service.

I finally got my aluminum tube needed for the shroud to cover up the adapter. Also bumped the power up to 75 fpe @ 135bar.



Going to stay like this for a bit. I pulled the PARD off the top and put on a cheap optima 3-12x50. Going to use my side shot phone set up on there and needed it to be lighter but big image.

Only other modification I may do, is get a dual tank adapter from Saber Tactical and run dual 350cc bottles. That would also let me go up to a bigger moderator which it definitely needs.

test fit some of those NSA slugs into the barrel and see if some of them would simply fall right through the liner with zero resistance, unless you have those fancy measuring tool to check all the slug diameter to see if there's any discrepancy in size?

I just backed out the plug that the stock attaches to.

I managed to finally get the valve and poppet to seal together.

It took about 4 hours and 5-6 times opening up the valve area.
I finally think I managed to burnish that valve to perfection.

I tried a rotary tool first 3 times, but on last try I did it by hand and that worked.

I also got the barrel out and cleaned it, and also got the trigger out and polished/lubed the trigger parts.

Great hunt, shooting and pic!

I had a blast as well! The cherry on top was Adam (my son) and I were squaded together (we only had the one gun) and we were within a shot or two of each other the entire match. It came down to the last lane and his last shot on the last target to tie me. No pressure, right? Of course he wanted to beat me but his options were to tie of lose. He squeezed the trigger and Tango down for the tie.
Cost me a chicken dinner at the Chicken Shack too.

Yep, what Tibor said

Awesome, looks like the best option I've found for my next pcp. Thanks for the information Forrest!

Can whacker said:

You make a good point . Got to have the right space for it. Which I fortunately do. I shoot from a second story window while sitting.
I have a 25M range in the corner of my yard ,which is off an alley. It's all good.

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Own wooded lot beside my home so angled off my rear porch I've a range with backstops @ 50 and 66 yards. Next road over has 4-5 empty lots in a row so nothing but woods behind. Angled range puts backstop behind widow's property, on far side of my wooded lot, about 40 yards into woods. She smokes in a screened back porch so "ticking" of pellets into soft wood backstop is most she'll ever hear from me. WM

Ezana4CE said:

About 10-15 minutes ago I thumped a good sized sow

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For members that are interested, you can read about this impromptu hog hunt in my social feed (in my profile) dated November 16, 2024. I didn’t recover a carcass and when you see the photos you may better understand why.

Fixing to order some nsa slugs for my 25cal p3. What size .249 .250, works best?

Two stand-out LW polygonal barrels come to mind...
1- .177/10.34 @915-920. 1:36 twist, prefers Slick 50 One lubed pellets. Clean it around 600-800 shots and it's happy. No fouling shots necessary after cleaning, 1st shot after cleaning goes right where it should.

2- .22/25.4 @ 955-960, 1:32 twist, prefers Gunzilla lubed pellets. Clean it around 300 shots and it's happy. Needs 10ish fouling shots right after cleaning for things to be good again.

Before I arrived at the above regimes, both needed cleaned much sooner. The lube didn't seem to make more accurate, just extended cleaning.

Generally I feel like poly barrels need cleaned more often than traditional 12 land and groove LWs. I've got a couple 12 l&gs that I'll shoot 4+ tins out of, unlubed, and not see any degradation of accuracy.

I have been filling two 30 minute and three 45 min SCBA tanks all the way to 4500 psi for over a year now and my CS4 is running as well as the day I put it into service with nothing more than the required grease knob turning when the hours are reached. I have a large "orange" secondary water trap and it has never had any water get into it, past the water trap built into the CS4 as long as I bleed the water off the CS4 about once every 15 minutes. Note that I do live in the desert. The built in water trap is very efficient to say the least.

I usually fill them first with my Yong Heng up to about 3000 PSI, then finish them off to 4500 PSI with the CS4.

A lot of shooters confuse spring canting with breaking in...

igolfat8 said:

How does your .30 barrel shoot? I had one many years ago and was not impressed with it so I sold it. The new owner wasn't either and then he said he cut the choke off and it started shooting much better. In all fairness I did not experiment with it very much and should have spent more time with it.

I was not aware the .25 was an LR barrel. That is interesting information. I've never been a fan of .25s for target shooting but they certainly have a place as a hunting caliber.

Thanks for bringing up the 20 grainers too. That is one pellet that I have not yet tried in any of my rifles. Is the BC discernably better than the 18s?

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My .30 barrel has potential. I shot it a few times at my brother’s house this spring where I have 100 yards - but it was in heavy wind conditions - April in Connecticut.

I just love .25 caliber - especially the 25.4g .25 caliber pellet. So I “stockpiled” a 2nd .25LR barrel, lol. You can utilize a much milder tune for .25 25.4g vs. .22 25.4g.

Both the .22 and .25 RTI Long Range barrels have the same slow 1:32 twist rate.

They only made the .25LR during the last year of P1 production. Most P1 .25s were produced with CZ barrels I believe.

I’m retiring at the end of this year, so I’m looking forward to spending a bunch of time at 75 yards with the P1 and .22LR .25LR and .30 barrels next spring. Then I’ll move out to 100 - but I’ve noticed that beyond 75, my wind reading skills are not up to truly evaluating the performance of my tuning on the various calibers.

Tomorrow I will not be able to host the end of the month's match. The next match is set for the last Saturday of November which is the 30th

GeneT said:

Get one and see how much you use it. I don't find that I do, but maybe I'm atypical. Also, PLA doesn't like to sit in the AMS, rewind and reload as needed, but don't let it set or you'll be fishing the broken pieces out.

I pretty much only use PLA from the rear spool now, and use other materials (mostly ASA) from the AMS.

GsT

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With 3 AMS's the possibilities are endless. Here is just a small sample of multi colored printing.

Xcaliber said:

Thanks for the tips, will do.

How often do you plan on yanking out the valve rod for cleaning/polishing? 1000~2000rd to keep it as clean and as consistent as possible?

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Well, I hope that polishing it plus getting some more shots through it will eventually get it to a point that there’s no more wear on the orings guiding it… for now I guess I’ll do it whenever I notice that I need more than 5ish shots or get back to tuned speed or whenever I have the gun opened up for whatever reason.

I didn’t grease/lube it since lube will eventually wear off and provide for its own source of inconsistency but if it gets bad within a 1000 shots or so again I might as well do that in addition.

athlon_oved said:

yup anything below 640 is not to great imho. i like the iray RH50R. the best bang for the buck, 640 resolution with LR and ballistic calc.

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That must be a nice thermal but over 5K! That cost more in a Schmidt and Bender scope!