Newbie notes: AA s400 mpr brain dump

[mcoulter]

OK, this will be a little brain dump on this rifle because I'm trying to learn it and the ins-and-outs of FT (specifically WFTF division).

I picked up a used Air Arms s400 mpr this past winter and I'm just about to the point where I can say that I know what its capabilities are. This gun started out as a 5.1 fpe sporter manufactured in 2005. It has had several owners and along the way has been pretty extensively modified. It has a longer air tube (the original was included) and is now regulated. I have to assume that it was ported or opened up along the way. 

Using the transfer port restrictor I can get a useful range of 755 fps (10.9 fpe) up to 877 fps (14.8) with H&N FTT pellets. I am getting 90 shots averaging 11.8 fpe with an extreme spread of 16 fps from a 200 bar fill. This was with the transfer port opened about 1/2 turn from being all the way in. The max velocity is reached about 4 full turns out. I know using the TP to limit velocity is not optimal, but I don't have much interest in opening this old girl up to mess with the hammer spring or regulator right now. I'm pretty happy with this tune. The gun came shooting pretty "hot" and I never was able to get it group well shooting that way. I think this gun is happiest at the 12 fpe level.

In my backyard bench testing I have it zero'd at 20 and 40 yards. I just read the Building a dope card for FT thread and will be playing with the mil grid target linked from it to see how I like it across the range of distances.

The gun came with a gigantic UTG scope and wheel which I'm not using. More out of convenience than anything else, I put on an Athlon 6-24x50 scope on it. I bought that scope used a while back and never really loved the reticle. It's pretty thick at 24x. However, I just tested a parallax wheel that came with a Discovery scope on the Athlon and found that it fits so that pretty much seals the deal in keeping the Athlon on her.

The gun arrived with an insanely light trigger. It was way too light for me (especially when shooting in the winter when it's hard to feel your fingers). I now have it set more firmly and in such a way that the trigger returns to "normal" when I get to the 2nd stage and release it.

So far I have only had to replace the pellet probe seal (inner barrel) and grind down the muzzle brake some more so it clears the end of the air tube better. At some point I may look to replace the muzzle brake with a Rowan air stripper. I am still curious to see if that could improve accuracy at higher velocities.

Now that I feel like I know the gun fairly well, I'll be getting off the bench, adding the hamster thingy and remembering how poorly I shoot when I am actually supporting the rifle myself... ;-)



Begin Pic Dump

 



68 yard target

Top row 40 yards, 40 yards, 20 yards
Bottom row 20 yards, 20 yards, 50 yards (1.25 inch drop / 3/4 mil)

 

[chasdicapua]

Beautiful rifle. Would love to see it in person. What part of the country are you in?

Looks like it's got plenty of accuracy for FT. If you ever have the money for a better quality, more powerful scope, that will help your range finding greatly. 

Enjoy the rifle.

Chas

 

[wildcj5]

Great rifles. I also have the 6ftlb version. I turned mine up by removing the tp restricter and adding a poly oring behind the hammer spring. This bumped power to just under 12ftlb. Absolutely love mine.



ignore the sleeping gopher.

 

[mcoulter]

Thank you Chas. I'm in Central New York. I think it'll be a long time before I find this scope to be a limiting factor in my shooting!

WildCJ5, it's hard to tell from the pic, but it looks like removed the front barrel band on your rifle. Currently, the front barrel band on my s400 does not have an o-ring. I hope to test accuracy without and then with an o-ring here.

 

[wildcj5]

Mine does not have a barrel band in the front but to be honest I don’t remember if it ever had one. I did swap the front gauge for a foster. The silver part the gauge set in had to be cut back some time allow for removal of the quick connect for filling.

I bought mine used and it already had the speed shop paint job. Guy owned a body shop. I think he painted it because the stock snapped at the wrist. I can see a slight line in the paint and understand it is a common issue with the 400 stocks.

I also added a square section of steel filled with melted pellets under the air tube. The stock has a section already there for weight. Made the rifle much more stable for FT shooting.

 

[chasdicapua]

I'll be at the Grand Prix in the Finger Lakes area in July. See you and the rifle there if you're attending. 

Also, extending an invitation to come to the Grand Prix we're having in Massachusetts in June. 

Chas

 

[dayjd]

Last July I picked up a Air Arms Pro Target which predates the MPR I believe and for sure the EV2. I played with it until August then put it away to shoot Benchrest Light Varmit in the fall of 2021. When I pulled it out in November all the Air had leaked out of the air tube. I shipped it to Joe Korick in Washington State and he resealed it for me. I only got around to shoot it one time indoor 25 yards and it shot pretty consistently in the low 240's. If I keep it (Right now I'm trying to trim my herd down to 3 or 4 airguns) I will be using it again next fall. My favorite two benchrest classes is Springer and Heavy Varmit. Recently I purchased a Vulcan 3 .22 to shoot the benchrest open class so I might have to drop one of the classes I already shoot at our USARB matches. Good Luck with your MPR and I'm sure if the stick in the FT Circuit we will run into you somewhere.

Bill Day

 

[mcoulter]

Thanks for the kind words and encouragement everyone! I feel I pretty much have the gun where I want it. 

I had a near-windless evening last night and I did some testing of the three different head sizes that FTT come in. The s400 seems to like the 4.50 and 4.51 best. Here are some 5-shot groups from 30 yards (rested).

And a couple clicks of scope adjustment got me aligned. Here was the group of the evening. I'd say the gun is accurate enough for me!

I think I have a decent handle on range estimation now. I did an initial setup at 5-yard increments on my scope wheel. I will be adding a few more distances next time I'm out shooting:

At roughly 800 fps with FTT, here are my holdovers with my scope at max magnification (24x):

10y = 3 mil
11y = 2 1/2 mil
13y = 1 3/4 mil
15y = 1.5 mil
20y = 1/2 mil
25y = 1/4 mil
30y = Zero
35y = 1/4 mil
40y = 1/2 mil
45y = 3/4 mil
50y = 1 mil
55y = 1 3/4 mil


This measuring is a bit tedious, so I made some distance markers using small white pine branches:

I've done this many times before to help me see wind, but this time I'm making these distance markers more permanent by driving small sections of pex piping into the ground.

I'm really looking forward to meeting folks at Rochester and/or Binghamton events  

 

[mcoulter]

I had some time this weekend to confirm that the holdovers I got from the bench are translating over fairly accurately to useful holdovers from 10 to 35 yards (so far...). I only had to do some small click adjustments on the scope to "null" out any differences between the gun on a rest vs. me supporting it from a seated on the ground position. I've been shooting at an Air Venturi Rat target that has 3 different sized holes:

Small = 14.8mm
Medium = 24.6mm
Large - 39.5mm

And here are some common fractional sizes converted to mm for translation:

5/8" = 15.9mm
1" = 25.4mm
1.5" = 38.1mm

On my target the small is a bit harder (smaller) than the 5/8 and 1" holes, but a little easier (larger) than a 1.5" hole. 

Here's a pic showing the medium sized kz:

I'll be shooting the small restrictor from 10 to 20 yards, repeating 20 yards with the medium restrictor and then using the medium out to 35 yards. At 35 I'll repeat with the largest opening and then carry that size out to 55 yards.

I did pretty well out to 20 yards with the small restrictor in the target. Then I started trying to take notes on how many knockdowns I got out of 5 shot attempts with the medium restrictor.

25 y = 1/5, 4/5, 5/5
30 y = 2/5, 3/5
35y = 2/5, 2/5, 3/5

Next opportunity later this week I will do 35 yards again with the largest kill-zone and move that out eventually to 55 yards (YIKES!). If I understand the Troyer scale, I think this is pretty close (using my rounded KZ sizing):

10y = 16
15y = 24
20y = 32 (20 with medium kz)
25y = 25
30y = 30
35y = 35 (23 with largest kz)
40y = 26.7
45y = 30
50y = 37.5
55y = 41.3 (yikes x2!)

Yeah, I can see how this can be kind of addictive! Oh, I did an average of these numbers and came up with a 28.4 difficulty rating.

 

[Deleted member 38071]

If you don't mind a tip here ya go. When you practice shooting don't move to the next/farther distance until you can drop the target ten times in a row. It can be a bit tedious but try it for 3 practice sessions in a row. 

 

[mcoulter]

If you don't mind a tip here ya go. When you practice shooting don't move to the next/farther distance until you can drop the target ten times in a row. It can be a bit tedious but try it for 3 practice sessions in a row.

I definitely appreciate the tip! I'm posting this info here to log it (so I don't forget it...) and to learn it better. But I also hope to get input like this too

Thanks! 

 

[chasdicapua]

Once you've got things dialed in. Don't forget standing an kneeling!

 

[guntherglow]

any ideas where that front fill adapter came from?

 

[mcoulter]

Howdy, sorry I do not. I purchased the gun used. It came with that longer tube and fill adapter. I know the OEM air arms banjo adapters are a pain... I had one on a s510 before.

EDIT - I just googled "Air Arms Quick Fill Conversion Kit" and got a couple of possibilities...

Air Arms S4/5xx Quickfill With Pressure Gauge By Huma-Air

Huma-Air quickfill assembly with pressure gauge for the Air Arms S440 and S500 series airrifle so you can easely check the fill pressure of your Air Arms.

www.huma-air.com

Air Arms Quick Fill Conversion Kit

Air Arms (All Models Excl. S200 & HFT 500) Quick Fill Conversion KitThis kit comes with everything you need to convert your standard Air Arms cylinder fill port, to a much safer and modern quick fill.The quick fill cylinder end comes with an in built gauge (0-250 bar) as well as a rotating...

www.theratworks.co.uk

 

[guntherglow]

Howdy, sorry I do not. I purchased the gun used. It came with that longer tube and fill adapter. I know the OEM air arms banjo adapters are a pain... I had one on a s510 before.

EDIT - I just googled "Air Arms Quick Fill Conversion Kit" and got a couple of possibilities...

Air Arms S4/5xx Quickfill With Pressure Gauge By Huma-Air

Huma-Air quickfill assembly with pressure gauge for the Air Arms S440 and S500 series airrifle so you can easely check the fill pressure of your Air Arms.

www.huma-air.com

Air Arms Quick Fill Conversion Kit

Air Arms (All Models Excl. S200 & HFT 500) Quick Fill Conversion KitThis kit comes with everything you need to convert your standard Air Arms cylinder fill port, to a much safer and modern quick fill.The quick fill cylinder end comes with an in built gauge (0-250 bar) as well as a rotating...

www.theratworks.co.uk

thank you, i figured but thanks for the links- huma said “no” - not a total no but idk but artworks looks promising- thanks i didn’t find that one myself

 

[gonzav71]

I had some time this weekend to confirm that the holdovers I got from the bench are translating over fairly accurately to useful holdovers from 10 to 35 yards (so far...). I only had to do some small click adjustments on the scope to "null" out any differences between the gun on a rest vs. me supporting it from a seated on the ground position. I've been shooting at an Air Venturi Rat target that has 3 different sized holes:

Small = 14.8mm
Medium = 24.6mm
Large - 39.5mm

And here are some common fractional sizes converted to mm for translation:

5/8" = 15.9mm
1" = 25.4mm
1.5" = 38.1mm

On my target the small is a bit harder (smaller) than the 5/8 and 1" holes, but a little easier (larger) than a 1.5" hole.

Here's a pic showing the medium sized kz:

View attachment 210772



I'll be shooting the small restrictor from 10 to 20 yards, repeating 20 yards with the medium restrictor and then using the medium out to 35 yards. At 35 I'll repeat with the largest opening and then carry that size out to 55 yards.

I did pretty well out to 20 yards with the small restrictor in the target. Then I started trying to take notes on how many knockdowns I got out of 5 shot attempts with the medium restrictor.

25 y = 1/5, 4/5, 5/5
30 y = 2/5, 3/5
35y = 2/5, 2/5, 3/5

Next opportunity later this week I will do 35 yards again with the largest kill-zone and move that out eventually to 55 yards (YIKES!). If I understand the Troyer scale, I think this is pretty close (using my rounded KZ sizing):

10y = 16
15y = 24
20y = 32 (20 with medium kz)
25y = 25
30y = 30
35y = 35 (23 with largest kz)
40y = 26.7
45y = 30
50y = 37.5
55y = 41.3 (yikes x2!)

Yeah, I can see how this can be kind of addictive! Oh, I did an average of these numbers and came up with a 28.4 difficulty rating.

Air Venturi Rat targets with reducers have metric dimensions. 15mm (.591"), 25mm (.984") and 40mm (1.575").

 

[scotton]

You are doing great. Here's a little practice input: 15 - 40 yards needs to be automatic. That's where you live as a new FT shooter. I would practice those distances with the small reducer 90% of the time, so you get more feedback. Practice small, miss small.

The close shots come down to gun accuracy, but you have to be accurate with the ranging. Luckily, they are easy to range even at lower magnification. So make sure your scope is dialed in for 10 - 15 yards (check out the half yards as well, course setters aren't exact with yardages) and make sure your holds are good.

After you are locked in for everything under 40 yards, then I would focus on long range targets and positionals. This is phase 2. Phase 1 should take a couple of weeks. Phase 2 will take anywhere from 2 to 40 years.