open sighted Diana N-tec 350 hits low with heavy grain pellets

[HectorMedina]

As the Brits would say:

"Jolly god show, old man!"

;-)






HM

[David110]

Top left is 10 shots of FTT, then I sighted to the barracudas with the other targets. The 10 shots bottom left are the final results. All @ 13-14 yards.

What's bizarre is the difference between the two kinds of pellets is 26 clicks (!) of elevation on the iron sight. That shot below the top right target was the first shot after switching from FTT to barracudas, landed like 4-5" below.

I wonder if a stiffer barrel (sleeved) could minimize this gap. Now normal grain pellets shoot straight with elevation tight all the way down, so any more barrel bending will make most pellets useless in this gun.

Wanted to thank you all, especially Hector and Peter, for the wealth of info, help, and encouragement.

[subscriber]

It works!

Are you going to post your sleeve / weight results to this thread, David?

[David110]

It works!

Are you going to post your sleeve / weight results to this thread, David?

You know I won't let this settle until I've tried everything 😂

The sleeve and weights seem like they'll take a while to arrive from China but I will come here to update once they arrive.

I measured the flares of the front dovetail and they are 16.3mm, the internal diameter of the sleeve I bought is 16mm. I've never dealt with carbon fiber so I don't know how much give it has, I wonder if I'll be able to tap it past the dovetail or if the .3mm won't be a problem or if I won't be able to use it at all.

I want to try the 18gr JSB's as well and see if they'll act like the normal grain pellets without a dramatic drop, or if they'll land halfway between the normal and the barracuda. If they land halfway, I'll bend it more and make this gun 18+gr since it's a magnum.

[subscriber]

It is highly likely that the CF tube will go over the small front site dovetail with light tapping.  It does depend on the wall thickness and weave of the CF.  However, the total increase in circumference at the dovetail is not very large, nor is it very long.

Be careful about not breathing in CF dust from the tube end cuts, or getting it in your eyes.  Before and after, a light wipe down with paper towel should take care of most loose bits.

[HectorMedina]

David,
On top of what Peter says, do understand that loose things create inaccuracy.

If you get shotgun patterns from the loose tube do not be disheartened. SOMETIMES just making sure that the tube fits real snugly at the REAR and at the FRONT is enough for a test. If you see a dramatic change, you can then decide to make the whole thing permanent.

Keep well, shoot straight and keep us posted!





HM

[David110]

It is highly likely that the CF tube will go over the small front site dovetail with light tapping.  It does depend on the wall thickness and weave of the CF.  However, the total increase in circumference at the dovetail is not very large, nor is it very long.

Be careful about not breathing in CF dust from the tube end cuts, or getting it in your eyes.  Before and after, a light wipe down with paper towel should take care of most loose bits.

I'll be using a dremel, wearing a mask and eye protection, and I'll choose a very windy day to work outside. It's a 2mm thick tube 20x16 https://www.aliexpress.com/item/32800195932.html?spm=a2g0s.9042311.0.0.21a74c4djM93o3

Hector, I'm all in on the sleeve. As long as there isn't a chance it will mess up precision when it's secured tightly (?), I'm willing to JB Weld it completely from the first installation.

[mpbby]

First of all, I would certainly try the JSB 18.1.

FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI.  Don't ask me why, just a mystery I can live with.

.............

Btw, a chrony is always a must to act as a probe to the inside parts health.
For instance .. https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0

Hector already said it, and so well.. an airgunner without a chrony is like a doctor without the stetoscope.

..............

Speaking of doctors, it seems to me you are deciding to put a prosthesis without testing enough the patient.

[Yogi]

First of all, I would certainly try the JSB 18.1.

FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI.  Don't ask me why, just a mystery I can live with.

.............

Btw, a chrony is always a must to act as a probe to the inside parts health.
For instance .. https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0

Hector already said it, and so well.. an airgunner without a chrony is like a doctor without the stetoscope.

..............

Speaking of doctors, it seems to me you are deciding to put a prosthesis without testing enough the patient.

Yea, he is amputating sprained ankle.  I bet it shoots worse, much worse...

-Y

[David110]

First of all, I would certainly try the JSB 18.1.

FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI.  Don't ask me why, just a mystery I can live with.

Have you tried your 350 with the barracudas after sighting with the FTT's?

[Dennis22]

 Carbon fiber is very brittle, like glass it has nearly zero elasticity.  I would expect it to split going over the sleeve

what you are talking about is a permanent fix, can not be undone  and not even sure of the out come.  think hard before you take that step

For a long range gun the most important consideration is accuracy, that would mean that at your 14 yard range you should be shooting one hole raged groups with your open sights.

second is a flat trajectory,  the heavy pellets will have a rainbow trajectory and range estimation will be extremely critical,   

Worry about POI after you get the accuracy dialed in.   

I have the referenced chronograph and it works well for comparing different pellets and consistency of velocity at under $30.00 it is cheep. You will know if your gun is with in spec

At this point I would recommend working on accuracy, and finding a pellet and hold that your gun likes,

Last you did not say what long range was, but I think most would consider it to be out side of 50 yds.

Dennis

[HectorMedina]

Hector, I'm all in on the sleeve. As long as there isn't a chance it will mess up precision when it's secured tightly (?), I'm willing to JB Weld it completely from the first installation.

No need for a first-permanent "installation".

Get some Teflon tape, the one that is used in plumbing. Then wrap some turns at the rear and some turns at the front.
Make sure you get a REALLY SNUG fit "screwing" the CF tube into the barrel.
DO check that the OD of the CF does NOT PREVENT A FULL COCKING STROKE!
If it does, then the "rear" of the sleeve should be where the CF needs to stop to allow you to cock the gun.
ONCE you have done this test, if it does not provide a dramatic change, then gluing the CF will not create it.
I repeat, the tape is to allow BOTH front and rear of CF tube to be fully supported and not wobble. FIT HAS TO BE TIGHT!.


HTH, keep us posted!





HM

[mpbby]

A long answer to a simple question..

David, a major landmark from my learning curve with the D 350 is to be so careful about not jumping to conclusions.  The thing is to pursue consistency of the whole team - shooter, rifle, aiming device and ammo.  The results come from an interaction of the players, and each one may be a cause to inconsistency.

When inconsistency occurs, you have to go step by step, carefully analyzing each player.  In my case, the shooter is always the first suspect.  Once checking the stock screws.., only when I am convinced about doing well my part, as a next step, I will check the rifle with a chrony, the aiming device, ..

Btw, when shooting open sights, the rear sight of my D 350 has a horizontal play.  So, before each shot I have to remember to push it to the side with my thumb.

All that said, I tried the Baracuda Match in 2017.  I had some good groups, but, the consistency didn't last, and I gave up.  Considering the other possible causes, I can’t have a ‘definitive’ conclusion about them not behaving good with this rifle. They were just not working at the time and I stopped using them.

At that time, at 20m, and no matter group sizes, the POIs of Baracuda Match were all about "3" inches lower than the FTT.

…………………………

I will insist.  No matter if higher or lower are your groups, you are not having good ones.  You have to find the right way to hold, rest and squeeze the trigger (adjusted to be light), and practice to be repeatable about each detail.   At “14” yards, and to start the shooter challenge, you have to be able to achieve 1” groups, and consistently.  Believe me, doing this you will learn a lot about your skills and your rifle.

Sincerely! Do not modify the barrel until you are more experienced with the rifle and pellets. It will just confuse your thinking about the basics.

[David110]

No need for a first-permanent "installation".

Get some Teflon tape, the one that is used in plumbing. Then wrap some turns at the rear and some turns at the front.
Make sure you get a REALLY SNUG fit "screwing" the CF tube into the barrel.
DO check that the OD of the CF does NOT PREVENT A FULL COCKING STROKE!
If it does, then the "rear" of the sleeve should be where the CF needs to stop to allow you to cock the gun.
ONCE you have done this test, if it does not provide a dramatic change, then gluing the CF will not create it.
I repeat, the tape is to allow BOTH front and rear of CF tube to be fully supported and not wobble. FIT HAS TO BE TIGHT!.


HTH, keep us posted!

HM

The teflon tape is a BRILLIANT idea, I'll do that and keep you posted.

[dtdtdtdt]

Did you consider the idea that I suggested as an experiment? 

Wrap solder wire around about three inches of the barrel muzzle end and tape it in place to see if the harmonic stabilizer effect will help.  Move it around on the barrel as shoot groups with different settings.  Cheap and done in an afternoon! With.no damage to the rifle

Also as has been suggested several times, try different weight pellets.  When I was testing pellets, I found one particular pellet of good reputation, that gave me a 7"  5 shot group at 20yds while the best groups were less that 0.4" under the same conditions. 

Do the easy and cheap things first before any permanent or potentially damaging things first!

[dtdtdtdt]

https://hardairmagazine.com/reviews/diana-panther-350-n-tec-air-rifle-test-review-22-cal/


this review of the 350 N-Tec 22 cal from several years ago.  Best information is the table of pellets tested.

If you can find or have a ballistics program you might be able to determine whether the excessive drop is reasonable???

Dave

[Yogi]

David,

It sounds like David110 is going to do what he is going to do.  Does not matter what you tell him.

-Y

[David110]

Did you consider the idea that I suggested as an experiment? 

Wrap solder wire around about three inches of the barrel muzzle end and tape it in place to see if the harmonic stabilizer effect will help.  Move it around on the barrel as shoot groups with different settings.  Cheap and done in an afternoon! With.no damage to the rifle

Also as has been suggested several times, try different weight pellets.  When I was testing pellets, I found one particular pellet of good reputation, that gave me a 7"  5 shot group at 20yds while the best groups were less that 0.4" under the same conditions. 

Do the easy and cheap things first before any permanent or potentially damaging things first!

Sorry for the delayed reply, the new seal came in the mail so I've been changing and testing that.

If you see in my earlier post I did try taping some weights on to test as you suggested. It did cut down the distance of the drop a bit. I'm also waiting on pipe clamps as suggested by Peter, for a tighter fit. The soldering wire I have won't be enough to try your exact method but I'm looking forward to testing the pipe clamps in various places on the barrel. I don't think anything will bring the Barracudas up to normal grain pellets though. I'm not sure if you're following the whole thread but when I turn the rifle 90 degrees like a pistol the barracudas still land the same distance but to the right.

I also tried tightening the barrel hinge to stiffen it but that didn't change anything.

I have high hopes for the CF sleeve and the barrel weights that they'll fix the barrel with the barracudas. In the end, as everyone says, they simply may not be the pellets for my gun. I just enjoy solving problems 

[dtdtdtdt]

Sorry about being repetitive.  I must have missed that post.   The result of the harmonic stabilizer should be to reduce group size rather than drop.

[subscriber]

Sorry about being repetitive.  I must have missed that post.   The result of the harmonic stabilizer should be to reduce group size rather than drop.

You appear to have missed the underlined statement already made, also