Taipan veteran velocity vs group testing

[Dave]

My order from Neilson specialty Ammo arrived Saturday, so I started the slug hunt today.

Equipment: Taipan Veteran Long. 25, Vortex Diamondback tactical 6-24x50 EBR-2C reticle, Donnyfl Tatsu, Donnyfl speed dialer, and Competition Electronics ProChrono.

Slug candidates are NSA 26.8, 29.0, 29.5, and 33.5. 

The 26.8 and 29.0 are dish backed, while 29.5 and 33.5 are flat backed.

(Marked speed dialer at one of the through hole locations for reference point.)

The regulator is at whatever the factory set it to, and I started with the speed dialer set to just allow the gun to cock, plus slightly less. 

I shot a 5 shot group with each slug, and then reduced to next position and shot another string for each at 12 yards. Each 20 shot string dropped pressure from 250 Bar to about 180 Bar by gage, which should allow for about 30 shots before needing to refill. To make things simple, I just recorded the Avg velocity per ProChrono for each group.( All groups shot from magazine. )

The first groups allow me to establish a baseline to compare the adjustments, with speed dialer at 2 O'clock. I backed off the adjuster to the 12 O'clock position for group 2.

String 2 shows that there is promise with 33.5, 29.0 and 26.8 gr slugs, as I realize that some slugs don't stabilize at shorter distances, this shot string gives me hope that I will find one that groups well at longer range. 

For group three I backed off to 11 O'clock for 33.5 and first two of 29.5, and after seeing what was the same velocity average, I backed off to 10 O'clock position. The split in the 29.5 average refers to the 913 for shots 1-2 and 908 for Shots 3-5. Shot 1 was the 2nd from bottom, and 2 was the 2nd one from top for the 29.5 NSA.

At this point the groups started opening up, so I suspended testing to review results and determine best path forward.

Things I noticed:

The first thing is that from the first string to second string there was no difference in avg velocity to the 26.8gr slugs, but the group really tightened up, with the exception of a flyer. 

Second, The adjustment between groups 2 and 3 while it didn't produce velocity change, before I decreased the adjuster further, but groups started to open up. 

I don't know if these shall adjustments that don't seem to effect velocity so much might have something to do with barrel harmonics or efficiency of everything. Have anyone else experienced this?

I think I will have to g back to the 11 O'clock position and shoot the 26.8 and 29.0 to see what groups this produces. This should help me narrow down the speed dialer position to make my time doing 50 yard testing more productive. Once I narrow it down to a specific slug as showing the best accuracy, I will try making micro adjustments to see if I can tighten everything up. 

I found it very interesting that very little adjustment could change the results as much as they did. 

 

[mmahoney]

If your barrel likes the size of the slug, groups should all be touching at 12 yards. My guess is that your barrel doesn't like any of those slugs particarly well, but the 29.0 grainers look the most promising. I'd be surprised if making micro adjustments to the velocity makes much difference. If you collect more data by shooting more groups for each adjustment, I think you'll find the average group size stays the same at each velocity.

I haven't found my Veteran to be very sensitive to harmonic differences.

 

[Motorhead]

At 12 yards your JUST WASTING SLUGS.

 

[knifemaker]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife 

 

[mtnGhost]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

Yeah, they definitely prefer faster than slow. 1100FPS has been the magic number for most of the slugs that I've shot. The heavier ammo isn't as speed picky though, they'll group consistent at anything above 800. The lighter ammo shoots very well, sub-MOA all day - but the faster they're shot, they group closer to 1/2".

@Dave, I'd expect nothing larger than a single hole about a hair over the size of the projectile diameter. What are the first two digits of your Vet's serial number, and did you buy the rifle new or used?

 

[Guest]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

.25 Veterans are Lothar Walther barrels.

 

[rangur1]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

.25 Veterans are Lothar Walther barrels.

Not all of them. I have 2 25 cal vets , both CZ

 

[Dave]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

Yeah, they definitely prefer faster than slow. 1100FPS has been the magic number for most of the slugs that I've shot. The heavier ammo isn't as speed picky though, they'll group consistent at anything above 800. The lighter ammo shoots very well, sub-MOA all day - but the faster they're shot, they group closer to 1/2".

@Dave, I'd expect nothing larger than a single hole about a hair over the size of the projectile diameter. What are the first two digits of your Vet's serial number, and did you buy the rifle new or used?

Does the location or serial number tell what barrel is being used?

And what is necessary to get slugs moving that fast ? Is it just adjusting the regulator , or are other parts needed?

 

[Guest]

Adjust regulaor up and get a heavier hammer spring to go faster with heavier projectiles

Or just shoot pellets

 

[mmahoney]

I disagree with some here that testing slugs at 12 yards is a waste. The goal is to see which ones have potential to shoot at long range. That potential can be seen at far shorter ranges (such as inside your house or in your backyard) and your data shows this. I think Motorhead is saying that if you intend to shoot ONLY at 12 yards then slugs are a waste of time, and he is correct. Slugs aren't better than pellets unless the distance is great. You can still get a good idea for how well/poorly the slug groups at much shorter ranges, though. At such a short range, none of your groups are good. Like mtnghost says, at that range you are looking for a group that is only slightly larger than slug diameter at maximum.

If you want to adjust the velocity, the easiest way is to increase the hammer spring tenssion. I wouldn't adjust the regulator pressure at first. See where tightening the hammer spring gets you and go from there.

 

[Guest]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

.25 Veterans are Lothar Walther barrels.

Not all of them. I have 2 25 cal vets , both CZ

Where would I look to see what make of barrel I have on my two .25 Vets?

 

[mtnGhost]

I agree with Motorhead. Slugs are for longer ranges. Such a short distance tells you virtually nothing. At least 50 yards for short range testing!

For what it is worth, I have learned that the CZ barrels like speed and groups fall apart at lower velocities. 

Knife

Yeah, they definitely prefer faster than slow. 1100FPS has been the magic number for most of the slugs that I've shot. The heavier ammo isn't as speed picky though, they'll group consistent at anything above 800. The lighter ammo shoots very well, sub-MOA all day - but the faster they're shot, they group closer to 1/2".

@Dave, I'd expect nothing larger than a single hole about a hair over the size of the projectile diameter. What are the first two digits of your Vet's serial number, and did you buy the rifle new or used?

Does the location or serial number tell what barrel is being used?

And what is necessary to get slugs moving that fast ? Is it just adjusting the regulator , or are other parts needed?

Sort of, but I'm pretty certain that you have an LW barrel.

It's hard to say what could be going on with the accuracy issues without knowing more and ruling things out. Are you shooting from a bipod / rest? Which optic are you using? (I.e., are you positive that your shooting position, optic, and mounts are not the issue?)

 

[Dairyboy]

I don't think Taipan ever used CZ barrels in there .25 Veterans. They started as LW and believe have always been LW and still are. .22s started as CZ then went to LW temporarily and back to CZ now. 

The CZ on the side of the breech doesn't have to do with it being a CZ barrel.

 

[Guest]

I don't think Taipan ever used CZ barrels in there .25 Veterans. They started as LW and believe have always been LW and still are. .22s started as CZ then went to LW temporarily and back to CZ now. 

The CZ on the side of the breech doesn't have to do with it being a CZ barrel.

This is what Tony at Talon Tunes said. I E mailed Taipan about this, but it is about 8 PM in the Czech Republic. I hope I get a response so we can clear this up once and for all. I would like to see some groups at at least 30 yards. I like not spending my coin on testing. Woody Chuck, out?

 

[Guest]

just got a E mail from Charlie Frear and he said to the best of his knowledge the .25 is Lothar Walther.

 

[jwrabbit123]

Hi I would like to add my thoughts on thread ,

First and foremost , slugs better for longer range , due to the fact they fly better then a pellet (Higher BC) , also Most slugs tend to be exact weight and diameter and weigh exact weights ,I do make sure I do sort all of my ammo for this reason , Plus slugs and get a bent skirt like a pellet to have it fly differently then ones which are straight , SO you doing good with your testing , just shoot 75 and 100 yds or more to get a real accuracy of your tune ,



1 shooting 12 yards with slugs serves no point , I have a few taipan veterans and can group better at 100 yds then your 12 yard groups , In My 25 veteran , I had a LW stock and I did upgrade it to a unchoked slug barrel , Mine shoots a few slugs sub moa here is my best preforming 25 caliber veteran slugs , 

1. NSA 36.2 gr

2, MP 48 gr

3, 40gr BT

Mine likes 920fps to 1010 fps

.OK barrels , I own 3 genuine cz barrels in 22 cal only , I never saw a CZ.25 cal barrel , I have seen many taipans with engraved CZ with LW barrels among other brands , I believe in USA many guns from dealers , were bought with out barrels and they were fitted by USA dealers in past , SOME dealers fibbed and SAID OURS are CZ barrels when they were not at all , 



I am sure Taipan if you dig around forums you will see this was true since the mutant , but moving forward they may have changed practices ,

The Taipan is a great gun for pellets or slugs , but for a good slug gun you need to add a bigger plenum , and or modify your valve manifold , and spring settings , and reg pressures to get them hevier slugs to go 925 to 1000fps ,



LOU

 

[Vetmx]

I don’t want to be another black cloud but all those groups are a no go. Personally I’ve never even considered shooting a slug a 12yrds but if any of my slug guns aren’t one hole at 30yrds, I don’t even waste any lead or praying for some kind of slug redemption at the distances where slugs matter. You have some more money to spend on other slugs then if that fails, you have to make the decision to go into the gun and up the reg. But in the end, your gun might never shoot them. How committed are you? 

 

[mtnGhost]

I'll wager a guess and say that it's the barrel chamber and/or choke/crown that are causing issues. The ammo should still shoot straight and true out of the barrel at that range.

Did you clean out the bore when you got the rifle? Most of them come from the dealers with that nasty protective film in the bore. That has to be cleaned out thoroughly, otherwise you run the risk of damaging the lands, rifling, and possibly the crown chamfer. I'd run some tight patches through it with Ballistol to see if there's any brown residue coming out of the grooves.

I would also want to do a few things to test the barrel bore geometry - like pushing some JSB King size pellets not slugs) through the bore to see how they feel, checking the chamber itself to see if it's damaging the ammo during the loading cycle (very common issue). If the choke is too tight, I'd want to polish that out some, especially if it's "abrupt". 

The crown could be causing that as well. I'd make sure that it's square, and make sure pellets aren't getting hung up on it when you push some through.

You could do all but the visual inspection of the chamber / throat without removing the barrel. You'd just need to be comfortable removing the top part of the action housing to get at it better. The only tricky part of that for someone that hasn't done it before, is the reassembly. It can be a little frustrating without experience (do not lose the little ball bearing under the cocking lever).

If you need help, fee free to ping me.

 

[Dave]

I think I discovered the reason for my findings.Here is the initial target with JSB 25.39 gr, but I am not sure of what distance. 

Anyway, I took off the shroud and discovered alot of lead powder all over the barrel and inside the baffles, which I cleaned off. During inspection of baffles and barrel to see the reason for leading I discovered tons of lead in the rifling of the chocked area of the barrel.

I tried to see how tight it is and tried pushing the head of a pellet into chock. It was going to take a good amount of force to even push the head in on the jsb 33.95's. This is the tightest chock I have personally come across. This means that my best bet is to find the smaller diameter slugs to try, as trying to find any good pellets right now is nonexistent. 

 

[Franklink]

I think I discovered the reason for my findings...........

I tried to see how tight it is and tried pushing the head of a pellet into chock. It was going to take a good amount of force to even push the head in on the jsb 33.95's. This is the tightest chock I have personally come across. This means that my best bet is to find the smaller diameter slugs to try, as trying to find any good pellets right now is nonexistent. 

Not surprised here, VERY VERY VERY tight chokes on the 4? OEM Taipan barrels that I've had in my hands. From Ukraine and Czech specimens. Even the 700mm CZ barrel that we put on a friends gun was overly choked, in my opinion and in comparison to other barrels that shoot well with less aggressive/abrupt chokes. I've stated before that I think Taipan's barrel specs (read "insanely over-choked") make them much better pellet shooters than slug shooters. 

Did you clean out the bore when you got the rifle? Most of them come from the dealers with that nasty protective film in the bore. That has to be cleaned out thoroughly, otherwise you run the risk of damaging the lands, rifling, and possibly the crown chamfer.

Curious on this one. What about the manufacturers protective bore film can cause damage to lands, rifling, chamfer? Are there abrasives in it? (I can believe that some Vet barrel bores may come covered in that greasy brown new airgun barrel protective crud, but just as an FYI, neither of my Vets came with the brown gunk in their bores).