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The HW 97K underlever spring-piston rifle: Part Three

# The HW 97K underlever spring-piston rifle: Part Three

Weihrauch HW 97K rifle.

## This report covers:

• First time
• Who cares?
• What have we learned?

Today’s report could be subtitled Watching the numbers. It popped out of what I wrote on Tuesday. That was the day I reported on the velocity of the HW 97K underlever air rifle. I saw something as I recorded the velocities — something that I wanted to touch on, but wasn’t sure how to approach it at the time. So I skipped past it but promised myself to return and find out.

Today I will lay everything bare  and show you exactly what I saw that made me wonder. Let’s look at it right now.

These are the velocities I recorded for Tuesday’s report. Do you notice anything odd about them?

## First time

You are seeing these strings for the first time today. I almost put them into Tuesday’s report until I noticed what we are about to investigate.

Look at the second and third string. Notice that the velocity for the first shot is the lowest for that string. In the first string the second shot was slowest.

Also note that in string three the velocity seems to increase at the end of the string. In strings one and two the highest velocity seems to be in the middle of the string. In none of the strings is the highest velocity at the beginning.

When I shot string two I wondered whether I should continue to shoot after reaching ten shots, because it seemed if I did the average would be higher than it was. Then I shot string three and REALLY wondered if that was the case! What I want to do today is something I did not have time for when writing Tuesday’s report. I want to run the same test again, only this time I want to see if the first three shots are generally slower than the rest of the string. I thought about how to do this for some time. If I shoot strings of 13 shots with each pellet, what will that show? Will the fact that I’m shooting the rifle more with each pellet speed up the first shots of the next pellet? Will the average velocity of the first ten shots in a 13-shot string be slower or faster than the last ten shots?

## Who cares?

I care — that’s who cares. I want to know if making a small change to my test plan will have an impact on the results. So that’s what I’m testing today. Maybe it matters and maybe it doesn’t. Or maybe it matters with some airguns but not with others. If I find that it matters I need to change my test plan just a little. If it doesn’t matter I will continue on as before.

In the second velocity test several days later this is what happened.

As you can see in the second test the velocities all increased a little. With the Hobby the average increase was 13 f.p.s. The Superdome increased by an average of 6 f.p.s. and the Benjamin Bullseye increased by 8 f.p.s., average.

The Hobbies velocity spread decreased from 20 f.p.s. to 19 f.p.s. The Superdome spread remained a steady 23 f.p. The Benjamin Bullseye spread went from 23 f.p.s. to a whopping 35 f.p.s.

Based on what I see I’m not doing anything with the extra three pellet velocities. The rifle is clearly breaking in and those three numbers are meaningless.

## What have we learned?

I have learned a couple things. In the case of THIS HW 97K and probably all of the same model, a break-in is essential and look for anomalies when the rifle is new. My first shots in each string did not seem to pan out the way I expected, so I will continue to test the same way I always have.

I didn’t bother doing anything with the last three shots in each string, as they just show that the rifle is breaking in.

Given what I see here I’m inclined to want to test the velocity again down the road. This rifle seems to warrant it.

Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.
Categories Air Guns, Education / Training Tags

### 69 thoughts on “The HW 97K underlever spring-piston rifle: Part Three”

1. “…as they just show that the rifle is breaking in.”

BB,
Roger that; Brad put a lot of pellets through my HW97 before she settled to a nice 870 fps average with the 7.9-grain Crosman Premiers, which proved to be very accurate in that rifle.
While that ~13.2 fpe may not have been the most powerful HW97 around, she had a very nice firing behavior that made her more accurate than I was capable of wringing out of her.
It was quite some time ago, and I didn’t write down Brad’s figures at the time, but I believe the velocity spread (after settling in) was 15 fps.
I never tested it again after that, as that was back in my pre-chronograph days (yes, I know…sad!).
But I did shoot the rifle…a lot!…and in practice sessions as well as matches.
I can honestly say, I never thought the gun threw any wild shots; there was never a time when I thought to myself, “What? I was totally on that target! It should have fallen down!”.
No, every miss (I was convinced) was due to nothing but operator error.
She was one sweet rifle…I truly hope someone is still enjoying shooting her to this day. 🙂
Blessings to you,
dave

2. B.B.,

Couldn’t it be as simple as conditions the groups were shot in?
I took a quick look at dew points, relative humidity%, and air pressures at Fort Worth, Meacham International Airport for the past three days:
Extreme Spread for dew points: 55.9 – 72°, relative humidity: 28 – 100%, air pressure: 29.90 in hg (1011.5mb) – 30.06 in hg (1016mb corrected to sea level) i didn’t bother with temperatures since you were probably in an AC space.
I don’t know exactly what day or even time of day but unless you have them recorded the small change in MV could be attributable to changed conditions.
Good Testing is a difficult task, as you well know, with too many things to control or take into account for most folks.
I’ll be interested in your continued results.

shootski

• shootski,

Because of my hospital visit I shot those strings last Saturday. And I was in my non air-conditioned garage. Temp was about 80 degrees F.

BB

• Texas in July? 80 is more like it, unless you hang meat in the garage. ;o)

• I do hope you were properly bundled up when you shot them. 😉

• B.B.,

“Temp was about 8 degrees F.” WOWSERS!!!
I thought you lived in Texas near the Dallas-Fort Worth area that temperature in an unconditioned garage would only be possible somewhere in Alaska or Canada!

;^)

shootski

• Okay, wisenheimers — BB made a mistake. It was 80 degrees F, not 8. 🙂

BB

• B.B.,

No! say it isn’t so! :^o

shootski, aka Wisenheimer

• shootski,

Really? I just thought I could be anal at times. You need to go back to work. You have just too much time on your hands. I have a bunch of things that need to be done around RRHFWA. I cannot pay much, but you will be fed good. Mrs. RR is a superb cook.

• RidgeRunner,

Anal…no i learned how to do lots of stuff as a Naval Aviator, flight instructor, Scientific & Technical Subspecialist, I also was an expert on the JAG Manual and intelligence laws, as well as a top rated linguist; so this kind of FREE analytical help for Tom comes quick and easy during my coffee breaks. AND…you do know what they say about FREE help.
Although i would love to Set a Spell with you and your fine woman…Right Now i’m busy gutting our house to bare brick and block walls and joists and getting ready for a complete renovation along with helping my wife with her significant medical issues.

shootski

• shootski,

I had forgotten it was free.

Mrs. RR sees to it that our home is constantly being “remodeled”. We will try to remember to pray for the healing of your wife. With you as her husband, I am certain she has enough to deal with. 😉

• RidgeRunner,

Fifty Two years of marriage many overseas relocations and soon adding another year to her life sentence with me; many of her friends have submitted her for Sainthood.

shootski

• Mrs. RR has been suffering for quite some time herself. We are truly blessed.

• Ridgerunner

Me too on being blessed. One lady has been married to me for 63 years. Took 6 years of persuasions before that.

Deck

• It took me seven years to persuade mine. I finally told her that I was leaving if she did not marry me.

3. B.B.

I still think you should tune it to the Max and then auction it off for charity. JMHO.

-Y

• I personally do not hope that he does that because I would have to bid on it and would cry when I did not win. Me crying is not a pretty sight.

4. Glad you are recovering BB,prayers answered. I am enjoying the springer reports of late.
We stayed home for hurricane Beryl because my Wife had surgery about the same time BB had His so She could not travel and pucker factor was high.
Things are getting back to normal here in Galveston county. Our power is back , now to finish the clean up. Funny thing Beryl did not get my mailbox but someone coming down my street served to miss an oncoming car in a curve ran into my yard and took out my mailbox. The piles of tree limbs create blind spots around the roads. Compared to Ike or Harvey this was a pimple from my perspective.

• SSC,

Maybe you should do what they do around here. The young boys in pick’em up trucks have a sport where they smash mail boxes either with baseball bats or running them over. Some people have taken to using steel posts in concrete and either painting the steel to look like wood or covering it with such.

Needless to say, the culprits are usually still there in the morning.

• “steel posts in concrete”

LOL! Like that RR!

Unfortunate that decent folks have to protect their property from low-lifes with nothing better to do than destroy stuff.

Now someone needs to design something that is a “more permanent deterrent” for porch-thieves.

Hank

• They have. Some people have taken to leaving Amazon boxes on their porches filled with doo-doo.

“Stuff happens”.

• RidgeRunner,

You must drink WEAK Coffee TOO…LOL!

shootski

• shootski,

My coffee cannot be seen through even when held up to a bright light. Navy coffee is weak. BZZZZZZZ!

• Vana2,

It’s inventor, Norman MacLeod, named the mine after a large medieval Scottish sword. Unlike a conventional land mine, the Claymore is command-detonated and directional, meaning it is fired by remote-control and shoots a pattern of metal balls into the kill zone like a shotgun.

shootski

• Shootski,

As the local grackles know, I prefer to eliminate the source of the problem – decisively! 🙂

Know about the Claymore and think they would work great! The noise could bother the neighbors and they can make quit a mess. But they would immediately eliminate the problem (and likely deter other porch-pirates).

Unfortunately, I suspect that a Claymore would be considered “excess force” and be illegal. Too bad about that. 😉

Cheers!

• Yeah, that just might be seen as a murderous “trap” or something by the DA.

I wonder what would happen if one opened the front door, stuck out a long gun and order the thief on the ground RIGHT NOW! The thief would probably laugh it off until the first round took out a tire on the escape vehicle, then the mirror, the windshield and then the occupants.

That, too, would be seen as to expansive and over-the-top. Probably get the householder arrested for discharging an arm within the city rather then deal with the thieves.

• LFranke,

Very likely. I do like shootski’s solution, but it is a bit over the top also.

I do not experience such issues as I go through the extra expense of having a P.O. box. I also have a quarter mile long driveway up a hill and through the woods.

Most porch thieves are way too lazy to climb the hill to see if there just may be a package on the porch. There are also a lot of places around here to hide the bodies.

“Worse case of suicide I ever saw. Shot himself in the back fifty-seven times”, said the Sheriff.

• Bouncing Bettys would work too, but supplies are hard to come by – and they would be illegal to use in most jurisdictions.

• singleshotcajun,

Glad you got your power back, to unpucker sooner than later, and you and your spouse are safe!

My spouse and i lived through hurricane Celia in Corpus Christi and a few less memorable ones in Pensacola on the Bayou Texar.

shootski

• singleshotcajun,

My house in Houston didn’t suffer any damage except a few tree limbs but we still do not have power. I had to trash the content of fridge and freezer and request asylum in my son’s.
Henry

• Henry_TX,

You moved into your son’s fridge/freezer?
If the freezer, i would suggest you relocate to the fridge pronto.
Hope you get your power back soon.
Stay safe,
shootski

• LOL! Still no news regarding the status of the repairs, save for a very confusing ‘map’ released by Centerpoint Energy (not a brand of optics) that creates more questions than answers. Criticisms are being leveled from users and authorities alike considering that this was a week storm. Oh well, hopefully my son and daughter in law have patience.
Henry

5. I have been considering acquiring another Weihrauch to live here at RRHFWA. I think you have convinced me that it should be an HW97K. I do not know if Weihrauch will continue to offer such, but it can now be had in a walnut stock. That would be nice.

Please do continue with your blog on this air rifle. It hurts so good.

• If, or when, I look for another HW, it’ll likely have the older Goudy-style stock. I had a HW77 in .20 with the full length barrel that was a great shooter. The additional length of the cocking lever compared to the shorter 97K model I have now made for a bit more cocking leverage.

• Derrick,

I do not have a .20. I would like to have one, preferably an HW. I do understand your preference for the longer cocking lever, but with the way I am, I just make it easier to cock. 😉

• I’ve long thought that the HW 77/97 powerplant is ideal for .20. Just lay in a dozen tins or so.

• Derrick,

If I should end up with a .20, you may rest assured I will stock up on that pellet.

• RR: I was one of the few to be able to purchase a HW97K .22 cal with the walnut stock. It was purchased from Airguns of Arizona as alas, Pyramyd didn’t get any. I have been told that these 97Ks with the walnut stocks are of a limited run, but that may just be sales hype. I must say that the walnut is truly gorgeous, but the fit and finish isn’t up to the quality of my TX200’s walnut. As I’ve fired both rifles under the same conditions, I find no difference in accuracy at 25 and 50 yards. I can’t hit the target at 100 yards with my Vortek tuned TX200 at all. The HW97 does have the accuracy to hit that target, but the misses there are on me, not the rifle. One last comment and then I’ll shut-up: cocking the HW97K is of noticeable more difficulty than my TX200. This difference may be due to the breaking in process of the HW97K. Both of these rifles are a joy to shoot. Ah . . . the good life. Orv

• Orv,

I am quite sure it will not happen but should one or both of those air rifles should decide to come to live at RidgeRunner’s Home For Wayward Airguns, they would be most welcome.

6. Automobiles once required a break in period especially the engine. At one time we were told to treat the engine with tender loving care for 500 miles or so. Later it was popular to run the engine at many different speeds during break in. Still later the “smart” thing was to accelerate quickly to a very high speed and then allow the vehicle to gradually slow to a stop without braking. Air guns aren’t autos but I’m wondering if there are best ways to break them in. Shoot one weight pellet only? Shoot many different weight pellets? Season the power plant as well as the bore using a favorite pellet?

This all may be too far fetched to make any sense.

Deck

• Deck,

I use the break-in period to shoot the under/over weight culls from sorting pellets and those pellets that have been put aside due to damaged skirts. Economy pellets are fine as well as I keep the good stuff for serious shooting.

I enjoy the break-in period. It’s the honeymoon where you get to know the new airgun. Find it to be a relaxing, casual time to shoot (usually off-hand) where there’s no pressure to do your best.

Hank

• Hank

Being a habitual scope, peep, dot switcher; I use the “fishing weights” and out of statistical control premium pellets during sighting in. Even open sights have been good to me since I found some compromise glasses that clearly focus the front sight while not blurring either the rear sight or target.

Deck

PS: Tip for IT and those who have delayed editing with IPads. Double click home button and sweep up the P/A blog which logs it off. Next restart the blog. Editing is allowed.

• Thanks Decksniper, I will give that a trial next time I have the issue.

• Deck,

Talking about break-in, I just went through that with my AA S510.

Other than a coarse TP (Transfer Port) adjustment, the S510 is not tunable without major disassembly and replacing parts so you have to find a pellet compatible with the factory tune.

I did a pellet check after 600-700 shots with no joy. Pellets were not stable and 40 yard group were an inch or better. Yuk!

After another tin and a half of break-in the S510 is shooting 40 yard, 5 shot groups around .300 CTC. The PCP likes 18.13g at TP=5 and 15.89g at TP=4.

Happy with that!

Hank

• Hank

Wow! That is a dramatic turn of events. Some folks would have given up on it and returned it as defective.

Thanks to you and LFranke for break in info I was hoping for.

Deck

• Hank: I don’t cull my pellets to that exacting degree. Part of it is using JSBs and H&Ns that have, in my world, very few such deficient units. I can, however, see that with some brands….

My break in for my springers is to use heavy weight and snug, if not tight, fitting pellets for a tin or two (one if 500, two if 200 per tin). I do this to give extra cushioning to the piston at the end of the power stroke. It likely slows the whole compression stroke as well. I don’t need the optimal velocity or power, just to given the new power plant some resistance and cushioning as the parts mate.

At the end of the break-in period, the piece gets a barrel cleaning to follow the one that was immediately done when the piece was unwrapped and unboxed at entry into the basement range. That first cleaning was with bronze brush, JB Bore Paste, some Sheath/Barrier Oil, and then a flow of felt pellets PUSHED through the bore until it’s clean. Maybe one last felt pellet with some Sheath/Barrier loading to relube the now naked rifling.

Thereafter, its a process of shooting tins of pellets to determine the zeros for the 10M range, secure the sighting equipment, and get the sights to be consistent over a couple of hundred shots. After that, it’s all fun and score-keeping on the standard 10+2 NRA standard air rifle targets.

Attention to the spring lubrication is also part of the drill. A few well-placed spring chamber lube drops are added to the spring and allowed to spatter and flow to lube it and the enclosing chamber.

Thereafter, it’s a 400-500 pellet interval between lube additions. One can hear a “squeak” if the piston seal begins to want for some lube and then add a couple of drops.

• LFranke,

I follow a regime of routine maintenance – inspection, cleaning, lubrication and checking fasteners for all of my equipment.

With each airgun on its own schedule, I keep track of things by assigning a tin (or tins) to the airgun and perform maintenance when the number of pellets/slugs is reached.

Works for me 🙂

Hank

7. Just spent a little range time with my new to me Gamo Bone Collector Gen3i. For shootski, the humidity was high, the temperature was high and it was wanting to rain, but no wind.

What I experienced with this Gamo was probably the worst shooting I have ever done. Of course, I was not expecting to do too well anyway. My main objective was to learn a little about this thing. Boy, did I. I guess you folks are going to want me to tell you about it. That will happen.

• RR

Bring it on! Will be fun to see if you tame it or show it the door.

Deck

• Deck,

It is far more likely to find the door on its own. We shall see. One thing I will do that BB could not is see if I can improve the trigger. I will also learn how to do that “artillery hold” thing with it. Perhaps, after a few hundred pellets, I will learn how to shoot this thing.

• Ridgerunner

I have one rifle I will call accurate that disdains the artillery hold. The trigger on my Stoeger ATAC prevents it. In addition to the high pull weight it has the same crispness as a wet sponge. But it performs well with what I call the “strangle hold” which is the same way one may choose to plink with an African Cape buffalo gun. To be fair this rifle had thousands of shots through it before it displayed 2 MOA accuracy at 25 yards with 10 shot groups which says something about an extended break in period. I can only wonder about its accuracy potential if the artillery hold was possible.

Your upcoming reports have much promise and especially so if you can solve the trigger hurdle.

Deck

• I have a Walther Terrus in .22 that acts the same way. My plan is to use it for practice simulating my deer rifle.

• That is what I hope. My Gamo CFX did not do the artillery hold but would shoot ten shots inside of a dime at twenty-five yards. At fifty yards you could not cover the “group” with your outstretched fingers.

• RidgeRunner,

Ah! The fun approach as opposed to the scientific method ;^)

What kind of bones are you intending to collect?

Have fun…we all need more of it. Even if a bit of it costs Tom minor loss of face : o

shootski

• shootski,

Two things at this point.

Fun is indeed my approach to these things. Science? Are you kidding me? Not on my hill.

BB is not likely to lose face with my shooting this Gamo. If I had not been curious as to how far Gamo had come over the years, I would not have bothered. You would have thought that with their acquisition of BSA they would have learned something. Nah.

• As to bones, they will likely be chicken. I cannot afford beef.

I have looked into the Sub-MOA barrels (submoa.com) there website is not more than a placeholder home page thus far. HAM has done a blurb on them and it looks like a very impressive investment in equipment. Their product may not matter to the average airgun duffer but just the fact that someone is willing to invest in barrel manufacturing of that expected quality will be good for our sport overall.

shootski

• As I read that article on HAM, I wondered how these new barrels will compare to those by Lothar Walther (the gold standard in my never to be humble opinion). Perhaps Tom will do a comparison for us one day using perhaps, his Avenge-X rifle with the interchangeable barrels. Orv.

• Hoppalong Doc,

I wondered if someone would bring up Lothar-Walther that has a significant presence in airgun and firearm barrel manufacturing. I think a major difference is in the rifling technique they are touting- Cut Rifling.
If you are REALLY interested this is a very definitive examination of airgun barrel making BY SOMEONE WHO HAS ACTUALLY DONE IT and done it very well: https://quackenbushairguns.com/Airgun_barrels.htm

I suspect the Sub MOA start-up is going to bring out all of the barrel “experts” on the various airgun blogs to opine on the barrel topic from a basis of abject ignorance. If you read the linked article and remember 80%, you will be more knowledgeable than 99.8% of the commenters. You don’t even need to actually try to do any of the processes.

shootski

• shootski,

I saw that also. It sounds as if they hope to find some manufacturers to come on board with them. I can think of one that may do such, though I do expect the premium to be passed on to the buyer. We shall see where this goes. Very likely they will market their products to more than just airgun companies.

• RidgeRunner,

We are blessed! Both in spouses as well as being present for the golden age of adult airguns.

At least one of the two Sub Moa barrel principals is from American Air Arms. I doubt building barrels for anything other than airguns is in there future. Why? Because so many custom and semi custom firearm barrel builders are already entrenched in that market. And, the metallurgy requirement is so different on airgun barrels.

But you never know….

shootski

• shootski,

I met Tom Costan in Kentucky when he was just getting things rolling with American Air Arms. In fact, I have a Hawke watch cap from him. That was quite a few years ago.