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How to align clamp on FSB ?

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
All-
I finally have all the parts and am looking to get a service rifle build finished.

Question- how do I get the FSB aligned to close enough to dial it in at range?

I have:
Flat top upper with Compass Lake Engineering A4 carry rear sight with the 1/4 MOA NM setup
JP clamp on FSB
18” barrel w/rifle length gas

I might be regretting the FSB with set screws to work off barrel flats to dial in but wanted the adjustable gas on the JP.

Bore sight?
Jig up on flat surface and use a rail/indicator?

Just get it close and hit the range?

Thanks
 
I've done a couple by pulling the rear pin, pulling the bolt, mounting the open action in the bench vise with a bore sight out the window.

Take a hard look through the sights to pick out a visible detail on the scene about 80 yards out, then find that detail or something close through the bore.....percussion adjust to match.

In the black at 100 yds.....
 
Start with the target at really close range, get the shots centered, then move target to a longer range and try again.
 
In general, for AR sight block, I just line them up perpendicular to the barrel. I square up the barrel in a mill vise with a purpose built square plate and an adjustable parallel, but you can square it up with the flats on an upper and get decent results. On standard sights, there is a 3/8 in. counter bore for the sight post. Just use an edge finder and standard mill techniques to center the quill over the barrel. Then chuck up a 3/8 gauge pin in the quill and run it into the counterbore.

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^^^^^^^

Thanks- Very sensible.
For some reason when a person doesn’t do something all the time it seems like a mystery and you nail it- just treat like any other damn thing that has to indexed and centered on the mill.
 
I use a clamp on rear sight (Colt), set to mechanical wind zero and a GOOD collimator. AKA a bore sighting tool. Sweany Site-A-Line has never let me down. Can usually get to within 1 MOA at 200 yards.
 
I use a clamp on rear sight (Colt), set to mechanical wind zero and a GOOD collimator. AKA a bore sighting tool. Sweany Site-A-Line has never let me down. Can usually get to within 1 MOA at 200 yards.

I am not familiar with that gear- will look into it.

The rear I have is top notch- National Match clamp on built by Frank at Compass Lake Engineering.
I would like to get out to service rifle matches at local club - I can chat the guys on the line up about gear when things open up again.
 
All-
I finally have all the parts and am looking to get a service rifle build finished.

Question- how do I get the FSB aligned to close enough to dial it in at range?

I have:
Flat top upper with Compass Lake Engineering A4 carry rear sight with the 1/4 MOA NM setup
JP clamp on FSB
18” barrel w/rifle length gas

I might be regretting the FSB with set screws to work off barrel flats to dial in but wanted the adjustable gas on the JP.

Bore sight?
Jig up on flat surface and use a rail/indicator?

Just get it close and hit the range?

Thanks

i think you might find the CLE barrel with flats will not play well with the JP front sight base. ?
That said , alignment, get the gas ports lined up. Center the sight by eye and then you can set your no wind windage zero with the front sight base as long as you are with in the gas port alignment.
IIRC the JP front sight base comes with provisions to pin the front sight once your happy with the placement/alignment.
If your going to shoot service rifle theres little need for adjustable gas port.
 
Thanks- honestly I got lost in the woods of aftermarket ar parts.
I bought A 18” fluted Faxon Heavy ‘match’ barrel w/rifle gas and the JP fits fine.
I found the CLE and WA sources late in the game.
If I had it to do again I would just pick up everything from CLE.

I’m am now and have always been interested in just basic marksmanship.
So much of the ar world is selling some version of tactical nonsense.

I ended up with near enough to service rifle build to shoot matches given the more open CMP rules.
 
Well how this washed out is not a surprise knowing who we are dealing with.
I screwed around and screwed around and finally just went to the range and bore sighted at 50 yards which got me in the black of a 50 yard small bore rifle target.

I then got tired fast of trying to figure out how I was going to get it dead nuts on so I didn't have to crank over the windage even one 1/4 MOA click.

Soooooo.... I just built a sight pusher like any honest person would:

6C8B3A60-BC6E-4A68-977B-C78FFF2EC706_1_201_a.jpg

Mounted on the rifle:

3B1BBE54-DF83-4BD9-80B0-65EB6AF0A650_1_201_a.jpg

And the result shot at 100 yards on a MR31 target:

4663658C-27F5-4AE0-A81B-C67AE673E6C7_1_201_a.jpg

That is a five shot 3/4" group done rested on a range bag under the rail and butt to shoulder with the A2 irons- I am happy camper both with the inherent accuracy of the ammo/rifle and my hold.

Maybe one more sight tweak needed to starboard before pinning the sight.
I am leaving it for now to work on groups so I can get started on positions for Service Rifle competition.
BTW- Midway has their nice Competition Pro shooting mat on sale this weekend 45% off which is $29 bucks out the door and a deal..

I am happy with this.
I have the pusher off the rifle so know the mass of the thing is not tuning the barrel and throwing shots.

Thanks all
 
Nice work, WOA used to make a dial indicator Mount to adjust the windage adjustable bases, however now that Service rifle is all scope idk if he still made it. Good luck on competing. I earned my DR badge and HM with Irons and I’m proud of that. But I do admit I like using a scope now, my eyes aren’t so drained at the end of the day, but figuring out scopes was a problem too.
Anyway Hold Hard, build your positions every time, focus on that front sight, and squeeze that trigger.
 
Thanks.
I can still use irons and am thankful.
When I was shooting with the Bullseye league many would switch to dots for the few points it would buy them.
I am a tool user like most on this forum- I am committed to learning how to use the sights and enjoy getting there.

That above group was the best of the last range day but I want to see a consistent 1" at the 100 yard line and see if I can pull that lower than that.

I am just now returning to rifle and really enjoying it.
I shot NRA small bore as a kid and didn't touch arms till I started with pistol competition as an adult.
I still have the Win 52 from way back than and am working with that as well.

On the service rifle I am making good progress- nose to charging handle and my cheek weld plus front/rear alignment is getting locked in.
I am good on trigger after all the pistol work so just trying to sort out hold on the bulls- I was using deep six and have switched to six.
Vertical stringing is my error right now and I'm working on getting that sorted.
Deep six was vertical strings, center saw horizontal strings and six seems the roundest groups.
I have a .072" front post and .04" rear aperture with the hood off (Compass Lake gear).
Next trip out to range I am putting the hood back on and I am ordering a .038" to try.
Maybe step the post down to .062"...?
I have a dead clear front post with rifle length gas on this setup.

I only have a couple of hundred rounds through the rifle and am still on the bench rested- I am about to get onto a mat and work on a proper strapped up prone position.
 
Have you tried a wider front sight? I got my SR DR shooting a M14 on a ARNG team. We started with the .062" NM blade but it would cause elevation issues at 600. Went to a wide blade that appears the width of the target frame at 600. Use the frame for windage and just touch the bull at 6 o'clock for elevation. I would use a center hold for 200 offhand, since the bullet goes where the tip of the sight is, as long as the tip is wobbling in the black, you will shoot at least a 9, percentages say that you will get 10's and X's. Also easier to call your shots, and you always have some wobble offhand. Went back to 6 o'clock for 200 sitting. Shooting International I used aperture sights,but again put a blade in for offhand and used a center hold. This worked for my International Distinguished badge.
 
Thanks for that.

I have a .072" front post in the rifle now.

I am not in the finer is better school as from long pistol work I find large gaps on rear and large front an intuitive setup.
I just wanted to try the .062" in the off chance I find it a better fit for me.
I am getting very good depth of field with the .04” rear aperture- crystal clear front post and just slightly blurry bulls.
 
Don’t concentrate on group size, concentrate on consistency and keeping it in the x ring which is 3 inches at2/300.
I can’t say this enough , position / NPA is crucial
Especially in slow prone and offhand
I always finish last in offhand because if I put the rifle up and don’t like it, I break down and start over / adjust.
 
Ok- I REALLY need to get off the bench.
I have a proper mat coming in this week and will probably just use an old Carrhartt canvas coat for a shooting jacket to start.


Don't concentrate on groups?!
What?
That is all I ever concentrate on- I generally try to get consistent groups in my hold area, work on form to decrease hold area/groups and try to keep from throwing shots from bad habits on the trigger, shot release etc.

NPA is something I need to sort out- I have no ideal and have just worked a bit with the Win 52 to try to drag up old habits from 50 years ago..
 
Well I got off the bench and gave a proper slinged up prone position a go on the 100 yard line with reduced slow fire targets- I suck lol.

Well the first go at it in any case was a mess- tough to get cheek weld in the new position and clear view through the aperture.
I just tossed the rounds towards the target hoping for the best as I fought with it.
And got this:

2D7B882C-9E83-4456-99BF-D8F0B29A90D4_1_201_a.jpg

But... as these things go I settled down and sorted it out a bit by the third string;

A7DE41B1-912D-4B48-8675-1BBDA178FDB0_1_201_a.jpg

A ways to go but I have the gear sorted and just need to put in the range time.
But hey- I'm just in it for the girls...

FB1B3A79-DD14-4C5B-9C25-F30537C79A34_1_201_a.jpg

Thanks all
 








 
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