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An unintended coincidence                                                   ©

4/26/2022

4 Comments

 
PREAMBLE

Some weeks ago, a friend posted in a forum the difficulties he was having with an HW barrel in 0.20" cal.
I really do not know much about those barrels having used only one in my work and finding that the barrel I got had no choke. After the fact, it was noted that barrel blanks sold by HW to the US are unchoked, but it was a surprise for me. Since that experience, more than 20 years ago, I have used only L-W barrels. That particular HW barrel was mated to a PCP and a custom mould and shot those specific cast slugs very well, so the barrel was good, just not ideal for pellets.
Again, this was more than 20 years ago, and things change, all this to point out that I do not have too much experience with HW barrels.

Now, apart from the peculiarities of manufacturers about their rifling characteristics, there ARE things that are necessary in a barrel to be efficient, consistent, and accurate.
If a barrel is not uniform, it will not be efficient.
If a barrel is not uniform, it will not be consistent
If a barrel is not uniform, it cannot be accurate.

So, UNIFORMITY is what all barrels, regardless of maker, need to have in order to be truly good barrels.
You may forgive a bad efficiency if it is a short range barrel that is extremely consistent and uniform for the last couple of inches, but in a long range barrel or a hunting gun barrel, you NEED a certain amount of energy to break skin and penetrate, or simply fly to the target at 55 yards and beyond. THEN the last two inches is not "good enough".

And this was the case with the HW barrel in the discussion above mentioned. It had tight and loose spots, and the choke was overdone.

The maker was contacted and after a exchanging more than a few Emails, the barrel, breechblock, and linkage, are on their way to one of the distributors of the brand in the US. Hopefully, the local technician will accept the diagnosis and advise the maker to exchange the whole assembly.
The coincidence

By some quirk of fate, at the same time Midway put on a sale of a limited edition "Lawrence of Arabia" DIANA 34 EMS rifles. All in 0.177"

At the price offered (just a few bucks over $200), it was indeed a tempting offer and many friends took advantage of that sale.
Most have reported good results but, as in the HW case above, even the best makers put out a lemon now and then.
In this case, the rifle was not making even "F in Pentagon" (5.5 ft-lbs) power, so there were more than a few things wrong there.
The owner wanted anyway to have the powerplant changed to NTec (gas spring), and so we proceeded with the powerplant swap.
Picture
Powerplant swap
In the picture above you see on top, the OEM powerplant (two piece guide and spring), at the bottom the single NTec unit.
If you want to attempt the powerplant swap, you will need this kit:

Picture
The powerplant swap took all of 20 minutes, deburring the action, cleaning with acetone and then relubing with Ultimox 226, took another 20 minutes, and then testing begun.

Uhh-Ohh, not good, power was still very low, we exchanged NTec units, we changed piston seals and still no progress.

HMMMMMM So, we analyzed the barrel.

Good thing about the EMS is that everything is modular (as its name implies)
Picture
Once you remove the barrel hinge bolt (do note that there are Nord-loc washers on each side, so do NOT attempt to loosen the nut by itself).
​The barrel assembly can be taken out of the forks.
The cocking linkage can be removed with ONE SCREW (no cheap rivets here), and the side-bearing washers can be extracted with a magnet.
The barrel retaining nut can be extracted using the DIANA tool. 
Then the ORing falls and then the barrel can be tapped out. 
Picture
The block is NOT aluminum, but it is not a "hardened steel", so it marrs easily (previous experience, not this gun). Be careful if you want to work in these guns.
​
A long list of pellets were put through the barrel and a sad lack of uniformity was found that no lapping could repair. Looseness in the middle of the barrel is not something that is "correctable".

Picture
The full group of pellets tested
Picture
Deatiled view of some: PC FTT's, JSB H's, JSB Xact's
Picture
JSB's and Olympia
Picture
JSB 4.53/8.44
So, I sent the results of the tests to DIANA on April 6th, by April 7th I had the promise of a replacement barrel, by April 12th barrel was shipped.
We had to wait till April 25th to actually get it but, an hour after receiving it, the barrel had been "refined", was in place and shooting.
Fit was MUCH better, as you can see in these pictures:

Picture
JSB 4.53/8.44 on the left pushed to JUST BEFORE the choke, on the right pushed all the way through.
Picture
Same as above, but with H&N FTT's 4.52/8.66
The process of a barrel swap in the EMS is not complicated, but having done a few, I really have to admit that is not within the realm of the home tinkerer, not even the advanced ones. Things need to fit to each other within 0.0005" ; and keeping cylinders parallel to those tolerances is not easy when doing it with common tools.

While some may think that the "promise" of the EMS is not being followed through, the reality is that the EMS STILL holds substantial advantages for the shooter.
In this instance, a complaint that would take a month or more, was solved in less than 3 weeks. So, service is simplified and expedited.

It also opens the door for better, faster, customizations.

If you buy a LoA EMS at $207, and you want it in 0.22" that can easily be done for $100 more, you want it changed to NTec gas spring? $180 will get you there.

Hopefully, in the future, we will have more variety of barrels (short and long, threaded and not, etc.) and then it will be even more interesting.

In the end , it is all about what happens at the target ¿no? LOL!

Picture
Final test target showing part of the running-in and then 10 shot groups from the sitting FT position at 25 yards.
This barrel still needs some "running in" and I did not have time to test with GTO's which have proven surprisingly accurate in the latest DIANA 0.177" barrels.
But very clearly, the barrel shows potential, and at a little about 12 ft-lbs in an NTec config, it is an enjoyable gun to shoot all day, it has little recoils, no vibrations, and allows you to call and spot your shots easily.

As time goes by, the rest of the gun will also settle and all aspects will contribute to the shootability of these guns.

Keep well and shoot straight!






​HM

© 04/26/2022

4 Comments

    Hector Medina

    2012 US National WFTF Spring Piston Champion
    2012 WFTF Spring Piston Grand Prix Winner
    2013 World's WFTF Spring Piston 7th place
    2014 Texas State WFTF Piston Champion
    2014 World's WFTF Spring Piston 5th place.
    2015 Maine State Champion WFTF Piston
    2015 Massachusetts State Champion WFTF Piston
    2015 New York State Champion WFTF Piston
    2015 US National WFTF Piston 2nd Place
    2016 Canadian WFTF Piston Champion
    2016 Pyramyd Air Cup WFTF Piston 1st Place
    2017 US Nationals Open Piston 3rd Place
    2018 WFTC's Member of Team USA Champion Springers
    2018 WFTC's 4th place Veteran Springer
    2020 Puerto Rico GP Piston First Place
    2020 NC State Championships 1st Place Piston
    2022 Maryland State Champion WFTF 
    2022 WFTC's Italy Member of TEAM USA 2nd place Springers
    2022 WFTC's Italy
    2nd Place Veteran Springers

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