My Silver Kodiak is a whole new beast

[pgritty]

It is easy to over do the lubricants. Now that it is cleaned up maybe just shoot it more, shooting seems to be part of the breaking in process.
Good work,
Pat

[SagaciousKJB]

It is easy to over do the lubricants. Now that it is cleaned up maybe just shoot it more, shooting seems to be part of the breaking in process.
Good work,
Pat

Yeah this gun seems like it has a real Goldillocks syndrome when it comes to how much lube to use. I swear my B19 was nowhere near this finnicky; that was a one-and-done job.

After taking all of the lube out and running it dry, I eliminated the dieseling, but it dropped back down to 650 fps with the 14.3 grain.

H: 663
L: 646
AVG: 653
SD: 5

An SD of 5 is pretty good and the numbers were quite consistent, so I didn't see much reason to believe it would "settle" into better figures. Added a little bit of lube, first shot was back up to 699 with the 14.3 grain.

H: 699
L: 670
AVG: 684
SD: 10

It seems to have settled out a bit more the more I shot over the chrony as I tested the 17 grain Ruger Super Points...

H: 650
L: 627
AVG: 636
SD: 7

So I think NOW I should actually wait for things to settle and get more consistent numbers. Hopefully it settles back into the higher ranges produced as the lube is distributed, seal sets, etc. Though I have a feeling as the excess lube burns off, some of the energy will subside.

It's getting kind of frustrating. This gun produces 15-17 ft/lbs stock, so I'm really not satisfied with it running at 13-15 ft/lbs with a "tune".  I saw a video of a guy with a RS2 that he said had over 5000 shots through it, using the same 14.3 grain CPHP that I'm testing with, averaging 735 fps, and with great consistency. I could live with 50 fps shy, but if I am near 100 fps shy of that then I must be doing something wrong.

[Madd Hatter]

What elevation do you live at? The higher you live the less velocity you'll get. Find out what elevation others are getting their vel numbers at so you can compare apples to apples.

[Hoosier Daddy]

Great point Robert.

SagaciousKJB: I have a Silver Kodiak RX2 that is unmodified inside. I should be able to get you chrono numbers with CPHP this weekend if not before if you would like them.
 To Robert's point, I am at 1000' above sea level

[SagaciousKJB]

Great point Robert.

SagaciousKJB: I have a Silver Kodiak RX2 that is unmodified inside. I should be able to get you chrono numbers with CPHP this weekend if not before if you would like them.
 To Robert's point, I am at 1000' above sea level

I'm somewhere around 1100-1200 feet so I think that would probably be pretty close yeah?

How much does air temperature play into it too?

[Hoosier Daddy]

How much does air temperature play into it too?

Minute for a springer compared to Co2... I am ~68 degrees indoors.

[SagaciousKJB]

That's what I figured. I did some.chrony testing outside the other day when it was somewhere between 30-40 F but just remembered I posted numbers I got during summer weather, and they seem pretty close.

[SagaciousKJB]

Well, I have really been chasing my tail with this. I've had to have taken it down and put it all together again close to a dozen times or more over the last few days, trying different things...

Slight lubrication on the piston end (wipe on molly paste, wipe it back off), with a thin ring on the back end of the piston seal
No lubrication on the piston end, but a thin ring on the back of the piston seal
No lubrication at all
Slight lubrication on the back of the piston seal, slight lubrication on the piston end, and some clear-tar on the spring-guide only

And many combinations in between.

After reading back through my last few posts I realized that the only variable that I hadn't "put back the same way" when I reached 15 ft/lbs was the JB Weld buttons, so I put those back on and lubed it like I did when I reached that energy level (very thin layer of molly paste on the back end of the seal, slight molly paste on the piston end, no tar on the spring), and there we go, back up to 15-15.5 ft/lbs.  So apparently the JB Weld buttons did in fact do something after all?

Now another problem... With the JB Weld buttons on the piston end, and no molly paste, I'm getting some grinding on the cocking cycle. That was surprising since I figured the button should have prevented metal-metal contact, but I think since they are so thin (literally only a few thousandths of an inch) the buttons must compress a little and allow some metal-metal contact on the back of the piston during cocking, because of the way the cocking-shoe presses the piston up against the tube. So I put a little molly paste on the JB Weld buttons.  That seemed to help a little, but then the grinding came back after about a ten shots.  Not only that, but because the seal is dragged ALL the way back to just shy of the cocking-shoe insert, the front of the seal picks up the molly-paste that was left on the back of the piston-end, and kind of scoops it into the front of the compression chamber--so now it's dieseling again.  So unless I use a very little amount of molly paste on the piston's following end, it's going to gall and grind; but if I use enough to mitigate that, it's going to be picked up in the front of the chamber and cause dieseling.  It's not dieseling enough to cause detonation, but I'd still prefer not to have a smoky barrel and the smell of burnt molly paste.

It makes me really curious how others with this rifle lube up the piston-end enough to avoid this galling problem, but also avoid the seal picking it up and pushing it into the front of the compression tube. I kind of wonder if maybe people don't consider it "diseling" unless it actually detonates versus just smoking up the barrel. I could see people concluding that theirs is not dieseling under those conditions when it is in fact combusting the lubricant. If that were the case, it would also make me question how much of the higher energy levels of 16-17 ft/lbs I've seen are really attributable to combustion more than air pressure alone.

I also wonder why the energy level was so affected by the JB Weld buttons on the end of the piston.  I was just trying to replicate the conditions in which I achieved the 15 ft/lbs of energy, so added them back, not actually expecting them to make much difference. Like I said, I had tried dozens of different combinations without them, but as soon as I added them back, I got back up to that level again. The only theory I could propose about this is that without the buttons, the piston and tube are somehow coming into a greater level of contact during the firing cycle, just by merit of the tube not staying completely aligned, causing one side of the piston to make contact with the tube with a greater surface-area. By adding the buttons, it keeps it "straighter" and reduces the contact surface-area during the firing cycle, and so reduces the friction. However, as feasible as that theory may sound in my head, it doesn't really seem like the amount of friction that could be reduced is really that high, but on the other hand it seems like it can't just be a coincidence that after all the trials I've done, that I immediately get back to the 15 ft/lbs once I add the buttons back.

That goes back to the, "But what if it was just because it was dieseling," idea, because I do clearly remember it was dieseling during that prior trial where the buttons were present on the piston and I reached 15 ft/lbs, but also dieseling when they weren't present and falling shy of the 15 ft/lbs. So I do believe the buttons somehow help, but it made me look back at the numbers I've logged, and realize that during trials where I had reduced the dieseling substantially, it also had substantially lower energy numbers.

But it makes me wonder: Are the higher energy levels the result of the combustion, or is the combustion just an unfortunate side-effect of their being adequate lubrication that reduces the friction enough to reach higher energy levels.

I also have to wonder why even the most minute amount of molly paste on the piston end is being picked up by the seal and pushed into the front of the compression tube. I don't have this problem on my B19, but I have an over-sized seal on that. I think maybe the over-sized seal pulls all the molly-paste back on its cocking cycle, not allowing any of it to linger in front of the seal and end up pushed into the front of the chamber. But there's really not as many seal options available for this as there is for the B19, so I doubt finding an oversized seal for it is going to be an option.

Anyway, I'm rambling, but yeah I've really been chasing the dragon on this one trying to get those higher energy levels. I think I'm going to have to give up on trying to get it properly lubricated with molly paste and opt for some Krytox instead. That should show if the higher energy levels are really down to combustion or lubrication.