Yet Another M1S Upper Report

[Flewis]

I hate to start another thread, but didn't want to hijack anyone else's either.

I just got a new M1S upper (a week or so ago):

A3 Upper, 16" 1:8 twist with a chrome bolt and carrier (based on people's recommendations that the chrome bolt cycles easier... seems to work). Gas port is at the carbine position.

I cleaned the upper and lubed the bolt well.

Also, I'm using standard GI 20 round mags and a 6 position carbine stock with the stock spring and plunger.

Oh, also the gas port is .125. Strangely enough when I called M1S and asked if their .300 Fireball upper would cycle sub-sonics they said no. Then I asked what size the gas port was and after checking she said .125. I can't image it would be much good to shoot a super-sonic load with that size port and no adjustable gas system, but...

I'm setting this up for strictly sub-sonic 220 SMK loads.

Ran five rounds of H-110 w/9.2gns and the first two shots cycled completely, the remaining three ejected but did not strip the next round. They were all running slow at around 950 fps.

The next five rounds was 13gns of Reloader 7. All cycled properly and the bolt locked back after the last round. Ran about 1200+ fps. A little fast. I had one or two pierced primers, but no other pressure signs.

Last was five rounds with 11.5gns of 1680. Ran about 1050 fps on average and all rounds cycled properly. Also had a couple of pierced primers, but no other pressure signs.

I'm using Winchester small rifle (WSR) primers. I've read that they're a little soft (never had any trouble with my .223 loads though). I'm going to try some CCI-41 milspec primers next time.

Also, COAL was around 2.160

So far I'm very pleased. Today I'm loading up some more and am going to see how the accuracy is. I also picked up some PMags since everyone seems to like them.

If anyone's interested, I can post my spreadsheet with the trim to, COALs, brass and primer types, velocity's, etc.

[kdiver58]

I use CCI-450 primers with no problems ..

[kdiver58]

If you look at a few of my last posts .. we are doing many of the same things :)

My M1S upper will cycle some sub-sonics.. I found the trick with mine was the powder burn rate. I'm sticking with 1680 or slower ..

My M1S upper is a 1 to 1.5 MOA gun .. I consider it a base on which to build a better whisper .. After I get my suppressor and get it all dialed in I'm going to re-barrel !

[Flewis]

Yes, I'm going to stick with AA1680 also. It's given me the most consistent velocities and has always cycled the rifle.

Still experimenting with loads. I tried the H110 with a little hotter load and got around 1150 fps... still wouldn't cycle the rifle reliably so its out as far as my rifle is concerned.

I started out at 50 yards zeroing the rifle in. With the AA1680 loads I put five shots all on top of each other, pretty much the same hole. Moved it out to 100 yards and the group opened up to about 2 inches... but I'm blaming that on myself (it was hot, I was tired, and the target was in a heavily shaded area so I couldn't see it very well). Going to try again in a few days.

KDiver, what barrel are you looking at going to?

How do you guys deal with the amount of drop the Whisper/Fireball has at sub-sonic speeds? With my .223 varmit rifle I can guess the distances close enough to put a round in a 'chuck's head up to 200 yards or so. Looks like with the .300 I'll need a range-finder... it drops 4.5 inches from 100 to 125 yards if you zero at 100.

[kdiver58]

I mounted a scope with mil dots and lots of travel in the knobs. I was lobbing them out to 300 yards and had over 9 feet of drop :)
But I was able to hit a 12 by 12 plate at the distance..

BTW it's a Falcon Menace 10X

[snowhack]

Originally Posted by kdiver58

I mounted a scope with mil dots and lots of travel in the knobs. I was lobbing them out to 300 yards and had over 9 feet of drop :)
But I was able to hit a 12 by 12 plate at the distance..

BTW it's a Falcon Menace 10X

I fell in love w/ that scope just reading about it....saw it @ Sniper Central. How do you like it? Do you have the MP-5 reticle or Mil dot?

Sorry to side track. You can PM me so we can stay on track.

I have the M1S upper only w/ out the chromed bolt. Cycles like sand in your shorts. (it's pretty new yet) Will not cycle properly w/ H-110, Reloader #5 or #7. I was going to change up the gas port location and get an adjustable block, play w/ springs and buffers and more polishing of the bolt carrier. I'm going to try the AA powder first I guess. Especially since Bushmaster has a conversion kit for gas piston. (@ about $399.)


Wow sorry guys I replied to a post from the first page...should'a checked the lower right first.


Did you have the bore, grooves and lands checked w/ a scope? You may have had a lemony fresh barrel installed. My M1S upper is pretty consistant down range w/ all loads even being "pre-broken in". I inquired w/ M1S about the key hole forge marks out of curiosity and they told me of many diff forge houses supplying their cast parts. Not sure of the barrel man, but a lot of diff resources sometimes means a broad range in tolerence and fit. What about straightness and the crown? I know most times this goes w/ out mention for most here and I don't mean to insult intel, but you sometimes forget a thing or two.

[interceptor]

My barrel was recrowned at the same time as it was threaded for the Phantom adapter for the can, 11 deg.


<---- NOT a sastisfied M1S shopper...

[320pf]

Originally Posted by Flewis

I hate to start another thread, but didn't want to hijack anyone else's either.

I just got a new M1S upper (a week or so ago):

A3 Upper, 16" 1:8 twist with a chrome bolt and carrier (based on people's recommendations that the chrome bolt cycles easier... seems to work). Gas port is at the carbine position.

I cleaned the upper and lubed the bolt well.

Also, I'm using standard GI 20 round mags and a 6 position carbine stock with the stock spring and plunger.

Oh, also the gas port is .125. Strangely enough when I called M1S and asked if their .300 Fireball upper would cycle sub-sonics they said no. Then I asked what size the gas port was and after checking she said .125. I can't image it would be much good to shoot a super-sonic load with that size port and no adjustable gas system, but...

I'm setting this up for strictly sub-sonic 220 SMK loads.

Ran five rounds of H-110 w/9.2gns and the first two shots cycled completely, the remaining three ejected but did not strip the next round. They were all running slow at around 950 fps.

The next five rounds was 13gns of Reloader 7. All cycled properly and the bolt locked back after the last round. Ran about 1200+ fps. A little fast. I had one or two pierced primers, but no other pressure signs.

Last was five rounds with 11.5gns of 1680. Ran about 1050 fps on average and all rounds cycled properly. Also had a couple of pierced primers, but no other pressure signs.

I'm using Winchester small rifle (WSR) primers. I've read that they're a little soft (never had any trouble with my .223 loads though). I'm going to try some CCI-41 milspec primers next time.

Also, COAL was around 2.160

So far I'm very pleased. Today I'm loading up some more and am going to see how the accuracy is. I also picked up some PMags since everyone seems to like them.

If anyone's interested, I can post my spreadsheet with the trim to, COALs, brass and primer types, velocity's, etc.

Flewis,

Here is some load data from the Sierra manual for 220 gr MK. These are the starting loads, so you should not be getting any pierced primers. Even with the Winchester primers. (I use Winchester primers and have not pierced any primers. Even with the max loads that I have worked up to.)

I suspect that there is something wrong with the firing pin and/or the bolt/carrier. I would call M1 and ask them to send you another bolt/carrier and firing pin.

AA#9--9.4 1000 fps
2300--10.0 1000 fps
VN110--9.4 1000 fps
H110--9.9 1000 fps
W296--9.8 1000 fps
VN120--11.5 1000 fps
AA1680--11.7 1000 fps

320pf

P.S. Check out the pride fowler scopes. The 22LR has nearly identical ballistic trajectories and the 330-221 fireball sub-sonics.

[kdiver58]

Wow I need to check that out I have a Pride Fowler RR scope on my 10/22!

Oh I was going to order a Shilen barrel blank and machine my own.. But that's down the road .. K

[320pf]

Originally Posted by kdiver58

Wow I need to check that out I have a Pride Fowler RR scope on my 10/22!

Oh I was going to order a Shilen barrel blank and machine my own.. But that's down the road .. K

This is a bit off topic but people might find this useful.

Here are the ballistics for a Sierra 220 gr MK at 1080 fps compared to a Sierra 40 gr hornet varminter bullet at 1230 fps. I know that the 40 gr varminter bullet has a better B.C. but it still demonstrates the ballistic similarities between sub-sonic 300-221 fireball loads and the 22LR. Out to about 200 yrds., the ballistics are close enough. If you are looking for a scope to use with sub-sonic loads the Pride Fowler might be considered.


Calculated Table Sierra 220 MK at 1080 fps
Range Drop
(yds) (in)
100 -0.0
200 -30.8
300 -96.3
400 -199.0
500 -341.1

Calculated Table Sierra 40 gr at 1230 fps
Range Drop
(yds) (in)
100 -0.0
200 -32.9
300 -110.6
400 -243.9
500 -445.0


http://www.rapidreticle.com/img/22LR3-9.jpg

320pf