250Z 250Z tuning, mainly slugs.

[Bladefin]

Very interesting data! Yes HAM publishes this type of information in all our pellet and slug test reviews. Airgun Pellet Test Reviews Archives - Hard Air Magazine

In fact HAM reviews measure a sample size of 50 pieces for weight, length and diameter, as you'll see.

I commend you for measuring and documenting so many slugs. It's quite a task!

Of course results like this are the basis of why many top shooters sort their ammo.

I did spot check the diameters but didn't note them for each slug I measured. I was doing all this on a coffee table and didn't feel like taking the time to add that data to the sheet. The Xenforo site software also shifted the column headers one spot left when I pasted. It's a formatting issue I've seen with another site I help manage. Next time I'll put a header name in the 1st cell and it won't happen again. I'm going to add a cost per round in there next and I think the Zan will be close to the top there too.

I was amazed that the length consistency of the AEA and H&N didn't translate to weight consistency. The Wildman seemed to be garbage accross both but the lenght almost directly corresponded to the weight with them.

 

[Pumacarl]

I was amazed that the length consistency of the AEA and H&N didn't translate to weight consistency. The Wildman seemed to be garbage accross both but the lenght almost directly corresponded to the weight with them.

Now, I do find that interesting. I don't know if it's important or relatable to accuracy, but it is interesting.

 

[Bladefin]

Now, I do find that interesting. I don't know if it's important or relatable to accuracy, but it is interesting.

I don't know how much, if any, this info will correspond to down range results either. I do think that at 100yrds the poi will shift the most with the Wildman though. With one of them being a full 2 grains heavier it's going to drop for sure.

I was mainly looking for consistency vs cost. But again, that won't matter if the barrel doesn't like the most consistent slugs in a tin.

 

[Cantona256]

I don't know how much, if any, this info will correspond to down range results either. I do think that at 100yrds the poi will shift the most with the Wildman though. With one of them being a full 2 grains heavier it's going to drop for sure.

I was mainly looking for consistency vs cost. But again, that won't matter if the barrel doesn't like the most consistent slugs in a tin.

Not to beat a dead horse but this is why I use Franco’s… every 30gr has measured a consistent 30.1gr on the grain scale at work… every other one I’ve measured has been 31, 28, 32 ect… I have weighed every single one or even the majority, but every sample has weighed up as expected. They do have some variation in length but from what I’ve seen they are +/- .007

I know y’all are tired of hearing about it but I seriously don’t get anything for big upping him. Nor would I call myself an expert on airgun slugs but without a doubt they are better than any H&N, Apolo, Patriot Javelin and at least a couple others I’ve tried and can’t remember right now…. Oh and the best part is that they are less expensive than all of them too… there’s a reason I shoot 150-300slugs a week (when I can!) and it’s cuz they average out to about $0.10 each, depending on weight. But that’s including the shipping.

 

[Bladefin]

Here is a better version of the sheet. They are ranked by weight deviation from left to right. It's a shame the formatting in the sheet doesn't carry over from Excel to here and you can't attach .xlsx files either.

Round	Zan	30 Grain	AEA	30.2 Grain	H&N	30 Grain	Wildman	30 Grain
Count	Length	Weight	Length	Weight	Length	Weight	Length	Weight
1	0.315	30	0.2945	30.2	0.2895	30	0.3225	31
2	0.315	30	0.2945	30.2	0.2895	30	0.318	30.2
3	0.3165	30	0.2955	30.1	0.289	30	0.3205	30.6
4	0.3135	30	0.295	30.4	0.2895	30	0.3285	31.6
5	0.3165	30	0.295	30.4	0.2895	30	0.318	30.2
6	0.316	30	0.2945	30.4	0.289	30	0.335	32.8
7	0.3155	30	0.2945	30.4	0.2875	29.9	0.3275	31.6
8	0.315	30	0.295	30.4	0.289	29.8	0.3175	30.2
9	0.315	30	0.295	30.4	0.2895	30	0.318	30.4
10	0.3165	30	0.295	30.2	0.2885	30	0.3215	30.6
11	0.3155	30	0.2945	30.2	0.289	30	0.319	30.2
12	0.3155	30	0.2945	30.2	0.287	29.7	0.3195	30.2
13	0.315	30	0.2945	30.2	0.2905	29.9	0.3285	31.8
14	0.316	29.9	0.2955	30.3	0.29	29.8	0.32	30.6
15	0.312	29.9	0.2925	30.4	0.288	29.8	0.318	30.4
16	0.317	30	0.2945	30.3	0.2885	29.8	0.329	31.8
17	0.316	30	0.2945	30.3	0.29	29.8	0.319	30.4
18	0.317	30	0.2945	30.4	0.2875	30	0.318	30.2
19	0.317	30.1	0.2945	30.2	0.288	29.6	0.3355	32.5
20	0.3155	30	0.2945	30.2	0.2885	29.8	0.3205	30.6
21	0.3155	30	0.2945	30.2	0.2885	29.8	0.318	30.2
22	0.315	30	0.2945	30.3	0.2875	29.9	0.318	30.2
23	0.3155	29.9	0.2945	30.2	0.288	29.9	0.319	30.2
24	0.3165	29.9	0.2945	30.2	0.288	30	0.319	30.2
25	0.3165	30	0.2945	30.4	0.2885	29.8	0.3235	31.2
Average	0.3156	29.988	0.2946	30.284	0.2887	29.892	0.3221	30.796
Deviation	0.001095	0.043081	0.000529	0.096664	0.000884	0.112854	0.005294	0.76445
Cost/Rnd	$0.120		$0.068		$0.133		$0.200

 

[Pumacarl]

Let's talk about B.C. on the can matching real life results as computed by Strelok using a G1 profile. To wit, JSB KO .216 20.83gr supposedly have a B.C. of .088, on the tin number. I was shooting at 197y this morning and the only way I could get the Strelok numbers to match what was happening was to change my B.C. to .07. That's a big difference. My elevation is only about 480' above sea level, and it was 90 degrees and humid. I don't know how that would effect things but I do want to mention it. How are your ballistic profiles working for your slugs, and do they stay accurate out past 150y?

 

[Cantona256]

Let's talk about B.C. on the can matching real life results as computed by Strelok using a G1 profile. To wit, JSB KO .216 20.83gr supposedly have a B.C. of .088, on the tin number. I was shooting at 197y this morning and the only way I could get the Strelok numbers to match what was happening was to change my B.C. to .07. That's a big difference. My elevation is only about 480' above sea level, and it was 90 degrees and humid. I don't know how that would affect things but I do want to mention it. How are your ballistic profiles working for your slugs, and do they stay accurate out past 150y?

I have seen too many articles talking about the problems with using G1 for air rifles. So I only look at that number for as long as it takes me to divide by 1.950.. for the G7 coefficient. The DNT app only works with G1 and G7…. I have tested as far out as 187y and it worked almost perfectly. I suspect my 32s are getting a slightly better BC than advertised or the thin air helps… at about 150y I notice if the hold over is 3.6 mil then impact point will be like 3.5ish… so nothing major.

 

[Pumacarl]

I have seen too many articles talking about the problems with using G1 for air rifles. So I only look at that number for as long as it takes me to divide by 1.950.. for the G7 coefficient. The DNT app only works with G1 and G7…. I have tested as far out as 187y and it worked almost perfectly. I suspect my 32s are getting a slightly better BC than advertised or the thin air helps… at about 150y I notice if the hold over is 3.6 mil then impact point will be like 3.5ish… so nothing major.

Well, I'm not sure how to use what you're saying. I just inputted the G7 profile, the given factory bc, way off, then the bc I got and still way off. No way of making that profile work. G1 has always ended up being the closest for me, but in this case I have to tweek the bc down a lot more than usual. Just playing with RA4 and it is close but the best I have come up with now is still G1 using .068 for a bc. I am going to break out the ZAN's again and try those at 200 and see how they end up actually flying. If their flight matches their factory bc of .075 then they will actually be a better long range choice than the JSB.

I did manage to have fun today though. I hit my 5" hanging ball three times in a row at 197y off my tripod. Yesterday did not go so well, I was furious, ready to pitch my rifle, then I figured out what the problem was, and of course it was me. I just have too many airguns and airgun profiles in my phone, that I am constantly messing with. Turns out, after my intial scope error of losing track of my turret revolutions, that the gun I had selected in Strelok wasn't even my 250z. So today naturally went a whole lot better. So much stuff to keep track of, beware the man with one gun indeed!

 

[Cantona256]

Well, I'm not sure how to use what you're saying. I just inputted the G7 profile, the given factory bc, way off, then the bc I got and still way off. No way of making that profile work. G1 has always ended up being the closest for me, but in this case I have to tweek the bc down a lot more than usual. Just playing with RA4 and it is close but the best I have come up with now is still G1 using .068 for a bc. I am going to break out the ZAN's again and try those at 200 and see how they end up actually flying. If their flight matches their factory bc of .075 then they will actually be a better long range choice than the JSB.

I did manage to have fun today though. I hit my 5" hanging ball three times in a row at 197y off my tripod. Yesterday did not go so well, I was furious, ready to pitch my rifle, then I figured out what the problem was, and of course it was me. I just have too many airguns and airgun profiles in my phone, that I am constantly messing with. Turns out, after my intial scope error of losing track of my turret revolutions, that the gun I had selected in Strelok wasn't even my 250z. So today naturally went a whole lot better. So much stuff to keep track of, beware the man with one gun indeed!

dang I just ruined my one gun status!

This is really interesting information though please keep it coming.

 

[Bladefin]

Let's talk about B.C. on the can matching real life results as computed by Strelok using a G1 profile. To wit, JSB KO .216 20.83gr supposedly have a B.C. of .088, on the tin number. I was shooting at 197y this morning and the only way I could get the Strelok numbers to match what was happening was to change my B.C. to .07. That's a big difference. My elevation is only about 480' above sea level, and it was 90 degrees and humid. I don't know how that would effect things but I do want to mention it. How are your ballistic profiles working for your slugs, and do they stay accurate out past 150y?

I don't know when I be able to get out to a full hundred let alone two. The terrain here in north Georgia is very hilly being the lower part of the Appalachians. In the late fall when the leaves fall off the trees I'll range the furthest safe lane to shoot and see if it is past 70~80 yards. My current goal is to be able to hit a dime at anything under that distance. I may not even be able to shoot from November until sometime in the spring. I may be having major surgery in the mid fall.

I just got a DNT Zulus, at $500 I couldn't pass it up. I'll be digging into the ballistic tables soon. With Strelok, I haven't found a reliable place to download it yet. Not that I've look terribly hard. Since this is my first PCP I'm still trying to figure out the tuning code.

 

[Cantona256]

I don't know when I be able to get out to a full hundred let alone two. The terrain here in north Georgia is very hilly being the lower part of the Appalachians. In the late fall when the leaves fall off the trees I'll range the furthest safe lane to shoot and see if it is past 70~80 yards. My current goal is to be able to hit a dime at anything under that distance. I may not even be able to shoot from November until sometime in the spring. I may be having major surgery in the mid fall.

I just got a DNT Zulus, at $500 I couldn't pass it up. I'll be digging into the ballistic tables soon. With Strelok, I haven't found a reliable place to download it yet. Not that I've look terribly hard. Since this is my first PCP I'm still trying to figure out the tuning code.

You’ll get it bro… you’ve got the right speeds with your slugs and you’re already tight enough for hunting accuracy. I honestly feel the more I shoot my 250z the better it gets. I’ve been obsessive with it but I’ve seen those slug velocities creep up slowly but surely and it’s just glorious to shoot.

You’ve already done the hard work just be patient with yourself and take care of your health as much as you can! It won’t be long before it’s all “done” and you find yourself kinda sad that it’s all over haha

 

[Bladefin]

It's way off topic... but. The health thing is what it is. I have an ascending aortal aneurism (Think Jonh Ritter). The surgeon has been taking a wait and see approach for a few years, but last month told me I need to start thinking about having the procedure done. I'm going to have to have a section of my aorta replaced sooner or later and I've come to accept it. I'm thinking, get it done while I'm younger vs older. There's still a few dr visits and lots of questions I have. So nothing is set in stone for a time line right now. He!!, maybe the low recoil of the air gun will be good therapy once my chest is healed enough to shoot. We'll see.

This PCP tuning is so much different than powder, so many more variables. You start seeing what you want for a few rounds and think you're getting close only for the next couple to humble you. Time is my biggest issue with it. I'm hoping I can get a couple hours in this weekend.

 

[Bladefin]

I noticed that when I backed the hammer out the groups got better, out past flush and within fractions of a mm from the stock. I figured the slug kit was just too much spring for the 30gr slugs I'm shooting. So I pulled the kit spring out and put the stock on back it leaving the weight. The hammer is flush and the 1st 3 shots were dead on. Two making a large hole and one within a 1/2".

The thing is this made the gun a lot louder, like too loud. Should I keep turning the spring in and see if it quiets down some and what that does to the groups? The fps is in the same range to slightly higher 954fps to 968. I haven't fired enough to get a solid range of speeds.

Is the loudness due to too much air behind the slug? Should I drop the psi before messing with the spring?

 

[Bladefin]

Ok, I'm definitely going through more air, roughly 6-8 less shots per tank vs with the full slug kit. PSI at 2750ish (right between 2500 & 3000. Weaker spring with the setting flush.
Here's the last string in order 21 shots:
965.1, 964.7, 963.6, 962.8, 962.8, 961.3, 962.8, 959.8, 959.8, 962.8, 959.8, 962.8, 964.3, 964.3, 962.8, 946.3, 961.3, 956.8, 946.6, 946.6, 936.5.

The 1st 12 were pretty good, within 3/4", with a few groups in 1/2" 2 shots touching in each. The next 6 opened up to well over 1.5" and the last 2 tighten back up with the last one low off the reg. I'm shocked how loud it is, with my wife even complaining. Why would just adding a weaker hammer spring do that? No other changes.

I'm done until I get some feedback. I've got to quiet this thing back down!

 

[guitarplaya39]

Ok, I'm definitely going through more air, roughly 6-8 less shots per tank vs with the full slug kit. PSI at 2750ish (right between 2500 & 3000. Weaker spring with the setting flush.
Here's the last string in order 21 shots:
965.1, 964.7, 963.6, 962.8, 962.8, 961.3, 962.8, 959.8, 959.8, 962.8, 959.8, 962.8, 964.3, 964.3, 962.8, 946.3, 961.3, 956.8, 946.6, 946.6, 936.5.

The 1st 12 were pretty good, within 3/4", with a few groups in 1/2" 2 shots touching in each. The next 6 opened up to well over 1.5" and the last 2 tighten back up with the last one low off the reg. I'm shocked how loud it is, with my wife even complaining. Why would just adding a weaker hammer spring do that? No other changes.

I'm done until I get some feedback. I've got to quiet this thing back down!

I'm def no expert, but maybe the heavier weight is keeping the valve open longer, resulting in a bigger blast of air after the projectile leaves the barrel? Do you have a moderator? I'm hoping my slug kit will arrive today...

 

[Bladefin]

I'm def no expert, but maybe the heavier weight is keeping the valve open longer, resulting in a bigger blast of air after the projectile leaves the barrel? Do you have a moderator? I'm hoping my slug kit will arrive today...

The slug kit was in prior to swapping the spring backed to stock. It's definitely using more air, just don't know why a lighter spring would do that. As a noob to PCP's, I'm baffled. I'm shooting a 30 grain slug. If no one responds with pointers I might try a 32 & 34 grain to see of there's a difference.

My gut is telling me that the lighter spring is keeping the valve open longer without as much rebound after the strike. Thus using more air. Would just like confirmation that I'm on the right track and I need to lower the psi.

 

[guitarplaya39]

My gut is telling me that the lighter spring is keeping the valve open longer without as much rebound after the strike. Thus using more air. Would just like confirmation that I'm on the right track and I need to lower the psi.

I'm curious to know as well. Unfortunately, my kit won't be delivered until Monday now.
It could also be hammer bounce due to the higher pressure forcing the valve closed and throwing the hammer back into the lighter spring. That would also make the gun louder/less efficient. Maybe try more hammer spring tension to balance it out?
Sorry I'm not much help; I'm just itching to play when my kit gets here lol.

 

[Bladefin]

That's very possible, maybe even more plausible. I hadn't even thought a about hammer bounce and that would explain the air & noise.

 

[Pumacarl]

Now this is interesting, I know it's a pain for you, but it is interesting. I would guess hammer bounce too. To my understanding of it, dwell is a result of extra mass and force, but you reduced the spring rate and kept the mass, which is probably going to result in some hammer bounce. You are right in taking the mass of the projectile into consideration too. In a balanced system you need the air dispensed behind the pellet and the valve closed with the pellet just coming out of the barrel off of the peak pressure spike or it will be loud and wasting air. If you are there and that's what's happening and it's really accurate, then you have some choices to make. You could just keep it loud accurate and wasting air. Everybody will advise you not to, but hey, you are on an accurate node, do what you want. Just choose what's important to you, and go in that direction, meaning power, accuracy, quietness, or shot count. If you are after some super balanced zen-like experience, well then that's going to take you some time.

This is a situation where a bigger plenum and a lower reg setting could really help, I think.

 

[Pumacarl]

I think what you new pcp guys are doing with your .25 250z's is pretty amazing. You're getting a lot of performance out of a rather limited platform. This is probably going to be the most fun you have in the sport, trying out new stuff (to you) because you don't know not to try. None of of it is a waste of time if you're having fun. And you only remember what you did, not what you thought about, especially if you screw up. Good times.