953 Power Mods, Phase One.

[DavidS]

As I have ordered the Daisy 953 for this Project, it is time to begin the process of documenting this project.

This thread will cover the first phase of modifications to the coming Daisy 953, mostly targeted at improving the muzzle energy.

The task list for Phase One of this build is:

• [DONE] Order a new Daisy 953, so I have two 953's before starting.
• [DONE] Receive and un-box my new 953
• [DONE] Shoot it, get to know what pellets it likes out of box.
• [DONE] Fill the cavity in the piston head with epoxy.
• [DONE] Shim the pump tube forward a bit (as far as it will still draw air).
• [WIP] Shoot it, punch paper, plink, shoot.
• [DONE] Polish the trigger/sear contact points.
• [DONE] Weaken Trigger spring (not doing the 888 trigger this time).
• [WIP] Shoot and shoot some more.
• [TODO] Insert a shim to take more space from the air chamber.
• [TODO] Shoot a bit more.
• [TODO] Install a stronger hammer spring.
• [TODO] Polish out the transfer port/channel.
• [TODO] Install a weaker exhaust valve spring.
• [TODO] Shoot, shoot, and shoot a bit.
• [TODO] Order 888 front and rear sights.
• [TODO] Shoot a lot, and then a bit more.
• [TODO] Install the better open sights.
• [TODO] Shoot some more.

For comparative power testing I am going to pick a consistent material and measure penetration depth, to figure out how much improvement has been made.   This method has more meaning to me than chrony numbers anyway, I think some others would agree (and some would decent).

I intend to take my time on this build, to make sure I get it correct.   I am also going to thoroughly document the process so that I can quickly repeat it in the future while maintaining a high level of quality to my work.

I am hoping that after the first phase this will be a noticeably more powerful shooter (get heavy pellets past 500FPS).   Ideally it will end up shooting Winchester Domed pellets somewhere around 550FPS.

Once Phase One is complete I will begin working on Phase Two.  Phase Two will include making a custom pump tube, linkage, and piston to allow a slightly longer pump stroke (about 0.6 inches longer effective piston stroke), as well as some extreme accuracy mods.

There will not be a phase three, just one and two.

The overall goal is to end up with a very accurate Single Pump Rifle that produces enough power (with 9 to 12 grain pellets) that I feel comfortable taking vary small critters with it out to about 15 yards.   In other words bring it to the ability that Daisy misleading advertises it to have on there web site.

An interesting side note:

With CPL 7.9 grain pellets my current 953 produces 5.2FPE at the muzzle (545FPS).

This shows how much an improvement in efficiency simply using a heavier pellet makes with this rifle.   There is obviously a good bit of wasted energy with the lighter pellets, I would guess do to the time the air has to push on the pellet before it leaves the barrel.

I also find it interesting that it was possible for a CPL to get stuck in the barrel before the power mods, while the much heavier Winchester Domed never had that trouble.

Note on current 953:
When I received my current 953 (about 7 months ago) it was already shooting CPL's at about 515FPS (in one place I wrote 513FPS, in another I wrote 518FPS not sure which was correct).   That was before any power mods.

Power note on current 953's:
Most people are reporting that the newer 953's are doing between 505FPS and 520FPS, with CPL's, in stock condition.   Apparently Daisy fixed what ever the issue was that caused the older ones to shoot at lower powers than advertised.

**************************************************************************
I am going to add a note for the hunting naysayers:

Many a 2.5FPE Beeman P17 have been used to take squirrel, chipmunk, small birds, lizards, etc out to 8 yards, just requires a perfect head shot.    I agree that the Beeman P17 really is under powered, it does the job though.    That means that it is delivering about 2.2FPE to the target give or take.

My current Daisy 953, with its minimal power mods will deliver more than 4.6FPE to 15 yards (the max range I hunt with it), and is able to put more than 4FPE out passed 25 yards, at the maximum accurate shot range of 35 yards it will give 3.5FPE.

So yes a Daisy 953 can be used for hunting with a few simple power mods, a lot less than what I am doing to this one.    Unfortunately here in AZ .177 cal is not allowed for much, hopefully that will change in the future.

[DavidS]

Added two more items to the task list for phase one.  Things easily forgotten.

• [TODO] Receive and un-box my new 953
• [TODO] Install a weaker exhaust valve spring.

The first item is very important.

The second added item will help the hammer to open the valve more quickly, and hold it open a bit longer.

I do not know where I will be at the end of phase one, though I know it will be a lot better than where I started.

[DavidS]

I should add that the tracking says that I should receive the new 953 on Thursday the Tenth of September.

[DavidS]

Having done some figuring I realized that I will wish to keep the MV below 575 FPS, and the closer to 500FPS the better.   This is do to the 1:15 fast twist barrel used on the 953.   So I am editing my goal with this build to achieve between 5.7 and 7.2FPE.   The ideal being 550FPS with Winchester Domed pellets, that is 6.62FPE

My reasoning is that I know that every Daisy 953 that I am aware of likes Winchester Domed 9.86 grain pellets, and 575FPS with a Winchester Domed pellet is 7.2FPE while 510FPS with this pellet is 5.69FPE.

The problem with this is that my current 953 shoots at 512FPS with Winchester Domed pellets, that is already inside the goal range.   This means that I am going to have to be very careful not to overdue it when I get to the phase two mods.

In phase two I may have to make multiple sets of linkage, pistons, and pump tubes until I get down close to 550FPS with Winchester Domed pellets.   I believe it is highly possible that the extended tube will exceed this power level.   Ok when I get to phase two I will be using an adjustable piston, so I will only have to make one piston, the linkage done multiple times will be the real slow down.

An interesting side note:

With CPL 7.9 grain pellets my current 953 produces 5.2FPE at the muzzle (545FPS).

This shows how much an improvement in efficiency simply using a heavier pellet makes with this rifle.   There is obviously a good bit of wasted energy with the lighter pellets, I would guess do to the time the air has to push on the pellet before it leaves the barrel.

I also find it interesting that it was possible for a CPL to get stuck in the barrel before the power mods, while the much heavier Winchester Domed never had that trouble.

Note on current 953:
When I received my current 953 (about 7 months ago) it was already shooting CPL's at about 515FPS (in one place I wrote 513FPS, in another I wrote 518FPS not sure which was correct).   That was before any power mods.

Power note on current 953's:
Most people are reporting that the newer 953's are doing between 505FPS and 520FPS in stock condition.   Apparently Daisy fixed what ever the issue was that caused the older ones to shoot at lower powers than advertised.

[BigTinBoat]

The problem with this is that my current 953 shoots at 512FPS with Winchester Domed pellets, that is already inside the goal range. 

Might want to check your velocity with an actual chrony, I have serious doubts it's throwing a 9.8g pellet that fast.

[StevenG]

If you want to keep the velocity low, why not simply use a heavier pellet?

I agree with BigTinBoat.

[DavidS]

The problem with this is that my current 953 shoots at 512FPS with Winchester Domed pellets, that is already inside the goal range. 

Might want to check your velocity with an actual chrony, I have serious doubts it's throwing a 9.8g pellet that fast.

If you want to keep the velocity low, why not simply use a heavier pellet?

I agree with BigTinBoat.

You may be correct, that was done a while ago with a neighbors chrony, in a different state.    Eventually I will have my own chrony.        That is why I do the penetration comparison mostly anymore.

[DavidS]

The new 953 should arrive tomorrow, then I will begin the mods.

For a goal I have decided if the Winchester Domed pellet, shot from the 953, penetrates as far into a dense foam rubber material as the Crosman Hunting Pointed pellet from my 2240 I will be happy, and that will mark the end of mods.   As a heavy .177 cal pellet should take a lot less to penetrate the same depth as an average weight .22 cal pellet.

Do note that the first step is to shoot it as is out of box.   Then tomorrow eve when I take it apart it is going to stay apart overnight for the epoxy to fully set before reassembling.   Tomorrow eve when I take it apart I will be doing some trigger work and filling the piston head cavity.

[StevenG]

I don't understand that comparison. Those pellets are not the same shape nor caliber, nor do I believe such material would be uniform enough for this use. To me it seems like it tells you little to nothing about what is actually happening. The fact that these two pellets are not even the same lead alloy is going to make a huge difference. If one is harder, and the Crosman Pellets are quite hard, less energy will be lost to deformation which should change how deep they penetrate.

[DavidS]

I don't understand that comparison. Those pellets are not the same shape nor caliber, nor do I believe such material would be uniform enough for this use. To me it seems like it tells you little to nothing about what is actually happening. The fact that these two pellets are not even the same lead alloy is going to make a huge difference. If one is harder, and the Crosman Pellets are quite hard, less energy will be lost to deformation which should change how deep they penetrate.

Ok I see your point.   Do you have a decent recommendation?   I figure that the 2240 is likely doing around 8FPE and I want at least 5FPE from the 953 (5.5 to 6 would be great if I can achieve that).

The particular foam rubber I have is the most uniform density material I can think of, clay is less uniform, as are cans, and wood is quite poor, and I do not have the money to get something just for testing at this time.

[Trim Tab]

Hey David,
Just a sugestion if you haven't thought of it before hand; when filling the piston with epoxy mask the outside and over fill it
then turn it upside down on top of a flat waxed surface forcing the excess out, wipe away the excess with acetone and let it set up. you'll have a nice flat piston with out any extra work. watching for your up-dates

[DavidS]

Hey David,
Just a sugestion if you haven't thought of it before hand; when filling the piston with epoxy mask the outside and over fill it
then turn it upside down on top of a flat waxed surface forcing the excess out, wipe away the excess with acetone and let it set up. you'll have a nice flat piston with out any extra work. watching for your up-dates

Thank you for that suggestion.   I may well do just that, or very similar.

[DavidS]

I just received the new 953, and shot two clips empty with it.

It actually impressed me, the trigger is actually smooth out of box (I guess Daisy was listening to the one complaint), and it seems to be shooting at least as hard as my first 953 was when I got it (and it was a little hot compared to most).

I will be posting a review thread on it later today after I take a photo and get everything set up to begin modifications.

[DavidS]

STEP: [WIP] Shoot it, get to know what pellets it likes out of box.

So far it seems to be doing equally well with Crosman Hunting Pointed, Winchester Domed, and Gamo TS-10 pellets.   The TS-10 was a bit unexpected, even though I have had good luck with Gamo TS-22 (.22 cal) I had never had any luck with the TS-10's (.177 cal).

Though it surprised me with one pellet, the H&N Sniper Magnum 15 grain pellets seem to shoot a little better than the Winchester Domed, so far anyway.   None of my other .177's have liked any H&N pellet.

[StevenG]

Phone books using same brand and shape pellets might be an idea. Accuracy does not matter for that kind of test so no need to worry about what shoots best.

[DavidS]

Phone books using same brand and shape pellets might be an idea. Accuracy does not matter for that kind of test so no need to worry about what shoots best.

When I lived where I got phone books I used to do that.   No phone books here, thank you though.

[StevenG]

I still think using same pellets would be worth it.

[DavidS]

Sorry for taking so long in getting any further with this one.   As it is a new 953 I am still having difficulty doing anything other than shoot it when I pick it up.

I am also still impressed by how smooth the trigger is, with out any work at all.

Though I know that I will have to take it apart and make the trigger even better, get the piston head cavity filled, and shim the pump tube forward.   I am going to attempt to restrain myself from shooting it most of tomorrow so that I can get these things done.

[DavidS]

[WIP] Fill the cavity in the piston head with epoxy.

I just filled the cavity in the piston head with JB Weld Steel.  I filled it to the point of over doing it, so that I can sand it to level once it has time to set.

So in 4 hours I will sand it flat even to the piston face, then clean it up oil it and reassemble the 953.

[DavidS]

[WIP] Shim the pump tube forward a bit (as far as it will still draw air).
[WIP] Polish the trigger/sear contact points.
[WIP] Weaken Trigger spring (not doing the 888 trigger this time).

I am shimming the pump tube forward with a thin O-Ring cut to allow for the keeper slot epoxied onto the valve body where the tube slides on.

I am polishing the trigger/sear contact surfaces with some 1500 grit sand paper, using some 2400 grit to finish up.

To weaken the trigger spring I am holding it way way over-compressed for a few hours.