Sinclair F Class Bipod

[Rustystud]

I have never used the Sinclair BiPod but I have shot beside them being used. In the early days they were a handfull of issues. I understand they have come a long way. I recently bought two Centershot Bipods from John Weil. http://censhot.com/ I have been extremely pleased with both of them. They were on sale the other day.
Nat Lambeth

 

[memilanuk]

Here's my thoughts...

With a 'normal' bipod like the Harris BRMS 6-9" w/ the swivel head and notched legs mounted on a gun with a 'normal' buttstock with a bit of taper along the toe from the pistol grip to the butt... you have your 'coarse' adjustment in the notches in the legs, the 'fine' adjustment by sliding the rear bag forward or back a bit (think inclined plane) and the 'extra fine' tuning via squeezing the rear bag a bit. Pretty easy to manage.

When you put the same bipod on a gun with a flat toed stock - so it will recoil more 'straight back' rather than 'up', you lose that 'fine' adjustment and have to do more fiddling with the 'coarse' and then more work each shot with the 'extra fine. Still doable though.

Since there seems to be strong tendency towards the straight toed stock designs (like I said, they have their benefits), I think thats why a lot of people wanted that adjustable head on the Sinclair 'pod, or else get a setup like the Center Shot bipod (height adjustable via a mariners wheel). Its still far enough forward that most people won't be able to easily adjust from position (unless they have gorilla arms like me) but you'll get your 'fine' adjustment back.

If I were going to make one improvement to the Sinclair 'pod, I'd have them notch the legs like you see on a long-range front sight - the notches in one side nest in the corresponding grooves on the other side. That way you get more discrete movement (combined with a laser-etched scale, my #2 improvement)) and you get very repeatable setups. No more having a leg clamp come loose and the whole thing dump over sideways. Can you adjust it from position during a string? Probably not - I know I couldn't, and I'm 6'5". But I still think it'd be an improvement worth having, and probably something that could be relatively easily/cheaply during the existing production process.

Monte

 

[Rustystud]

http://i457.photobucket.com/albums/qq292/Rustystud_photos/NatRifles.jpg

Here is what we are talking about.

Nat Lambeth

 

[Killshot]

Some visiting shooters had a few of those on the line at the Canadian/American Long Range matches in Sacramento. Don't know that I noticed the mariners wheel at the time. Seems a bit over-engineered looking at the photo.

I'd like to draw something up for the Sinclair; maybe with a large thumbwheel that turns a fine-elevation adjustment and similar to Biggs' in the way it sits in the center of the structure.

No way to avoid the long reach, though. Wooger has it figured out. ;D

 

[280man]

Why don't you guys just give it up and buy a Farley. I know deep down inside you want to be cool like us open guys are

 

[Rustystud]

280man F-Class rules allows a bipod for F-TR, a Farley is an option for F-Open. I personally think Zeb and the Viper offer better options for F-Class than the Farley.
Nat Lambeth

 

[effendude]

Steve,
You guys need to come up to Mn. and shoot. At Elk River, we have irrigated firing lines that look just like the best golf courses! The grass is nice to lay on, and provides a place for the 2# mosquitoes to hide in. Seriously, the grass is nice. Shooting on soft ground would pose very different challenges and it looks like you guys have come up with some great solutions. I like your plate idea as it is rigid enough to not change its shape or elevation during a relay.
Scott

 

[Va Jim]

F-Class rules allow for a flat board under the bipod as long as it is not more than 2" wider than the bipod and no more than 12" deep. The attached image is mine. It is a 1X12, 21½" wide. I attached a handle to one side for carrying, counterbored and glued a Starrett bulls-eye level, applied two 6" wide UHMW strips for the bipod feet, and drilled three holes to locate my Farley rest when shooting F-Open. This was my prototype. I intended to paint the second one and make it look nice but the first one seems to work fine and I never got around to the second.
[/quote]

I was under the impression that a board was considered a table and not allowed under Fclass rules. What was the ruling at the last Nationals and does anyone have the actual NRA rule number.

Jim C

 

[Steve Blair]

Jim,

Attached are the F-Class rules. 22.3.4.1(b)(2) is quoted below.

QUOTE

(2) The use of any form of a table is prohibited. Separate flat boards or plates not exceeding the dimensions of the individual rests by two inches are allowed to be placed under the front and/or rear rests. In the case of a bipod, the board or plate may not exceed the width of the bipod by 2", nor be more than 12" front to rear. See Rule 3.4.1(a)(1).

No leveling screws or protrusions are allowed on these boards or plates. They must be flat on the top and bottom.

This discipline is a modification of high power prone shooting, not a form of bench rest and should not be construed as such.

Disabled competitors may apply to the NRA Protest Committee for appropriate dispensation.

The intent of this rule is to prevent the use of a table type device.

UNQUOTE

 

[Va Jim]

Steve

I just saw that and looks like it is time to start making one. Hope yours isn't patent or copyright because it looks good.

JimC

 

[Va Jim]

Steve

applied two 6" wide UHMW strips for the bipod feet.

What is this. Does it help the feet slide easier?

JimC

 

[Steve Blair]

Jim,

First, I freely release all ideas or concepts embodied in my "bipod plate" to any shooter who can use them.

Second, UHMW is Ultra High Molecular Weight polyethelyne. It is used for wear strips. Almost as slippery as teflon but much more abrasion resistant. The link where I bought it is below. I also wrapped the feet in tape and used paste wax on the UHMW. Yes, I wanted it real slippery.

http://cshyde.thomasnet.com/item/tapes-with-psa/uhmw-tape-acrylic-adhesive/uhmw-acrylic-adh-19-5a-6-5?&bc=100|1001|3001019|3001018

The one caveat is that natural position becomes more critical. The board surface is so slippery that any body misalignment will cause the rifle to move right or left in recoil. I had to work a bit on my position but have found where I need to be. Any deviation is immediately obvious. You could call that a problem or a benefit.

 

[280man]

The Farley comment was meant as a bit of humor. I shoot with a Farley because they are made in Oklahoma USA buy a great bunch of guys. I'm not knocking other rest but I buy locally if I can

 

[Taildrag15X]

Jim,

Attached are the F-Class rules. 22.3.4.1(b)(2) is quoted below.

QUOTE

(2) The use of any form of a table is prohibited. Separate flat boards or plates not exceeding the dimensions of the individual rests by two inches are allowed to be placed under the front and/or rear rests. In the case of a bipod, the board or plate may not exceed the width of the bipod by 2", nor be more than 12" front to rear. See Rule 3.4.1(a)(1).

No leveling screws or protrusions are allowed on these boards or plates. They must be flat on the top and bottom.

This discipline is a modification of high power prone shooting, not a form of bench rest and should not be construed as such.

Disabled competitors may apply to the NRA Protest Committee for appropriate dispensation.

The intent of this rule is to prevent the use of a table type device.

UNQUOTE

So doesn't the complete top surface need to be UHMW, as they are not , per the quoted Rules, "Flat on the bottom and top", the 2 rows of tape are similar to the "Rails" I've seen added to boards for the "skis" to slide in, which didn't make it past Tech.

"No leveling screws or protrusions are allowed on these boards or plates. They must be flat on the top and bottom."

Also don't think that the plate is legal for Open Class with your Rest, as it is limited by the "no more than 2" rule"

3.4.1 Rifle Rests -
(a) F-Class Open Rifle (F-O) - The rifle may be supported by any means which provide no positive
mechanical method for returning it to its precise point of aim for the prior shot. Subject to:
(1) No more than two rests may be used. If two rests are employed, they may not be attached to each
other.
(2) The use of any form of a table is prohibited. Separate flat boards or plates not exceeding the
dimensions of the individual rests by two inches are allowed to be placed under the front and/or rear rests. See Rule 3.4.1(a)(1).


I use a Harris, Pod Lock with Pod Paws on a 1 1/2" x 10" x 8" bare naked steel plate with a handle to carry it.

Or a Laberge on a plywood plate that's 7/8" x 27" x 12" for both F/TR & Open and even sometimes a Caldwell Rock BR which has a set of Super Feet and sits on the ground.

 

[Steve Blair]

Compared to what I have seen fired under bipods in national-level competition, the UHMW strips are optically flat. The board could easily be covered as you describe but currently fulfills the spirit of the rules. The strips serve no guiding function, whatsoever. As previously noted, lateral movement is much more obvious if the shooting position is not correct.

You are correct about the board size for F-Open. I have not shot the board in F-Open competition and will construct a correctly dimensioned model should I decide to do so. One of the hazards of overly restrictive rules or interpretations is restricting innovation. I am not suggesting that my solution is innovative but would not want to prevent someone from trying an idea that could benefit everyone. I note that the rules do not define "flat" and wonder what your steel plate would show if I ran a profilometer across it. Would it be truly flat? Within 32 microinch? I am not serious here, just trying to illustrate a point.

The impetus for testing my Farley rest on the board is that we have some mid-range matches upcoming and I wanted to try shooting my 17# 6BR Viper SS at 600. The testing went well and it appears to be a viable setup. I really prefer shooting my .308 F-TR at 1000.

 

[Taildrag15X]

When measured on a Surface plate it shows it is out .0010-.0015 across the corners, that is per the print I had it cut and surface ground by.

 

[Steve Blair]

When measured on a Surface plate it shows it is out .0010-.0015 across the corners, that is per the print I had it cut and surface ground by.

Well, it is not flat, then. Is that what you would like to see in a tech inspection? I guess you missed the point I was attempting to make. Sorry I was not clearer.

 

[memilanuk]

So now to hold an F-class match we'll need:

1) Scale capable of weighing up to 10+ kg, and resolving to the milligram level.

2) Outside micrometer wide enough to measure 76mm to three decimal places.

3) Optical comparator to determine if a board to be placed under the bipod or front rest is really 'flat' or not.


If we really keep going down this path, I may go back to Palma...

 

[FroggyOne2]

Palma is fun!

 

[Killshot]

The Farley comment was meant as a bit of humor. I shoot with a Farley because they are made in Oklahoma USA buy a great bunch of guys. I'm not knocking other rest but I buy locally if I can

No offense taken. My Farley comes on the Big Brown Truck tomorrow....

One reason I use a slippery fabric on the end of the mat with the Sinclair is that we shoot off of fine gravel. Rocking the skids fore and aft kinds of "beds" the skis so recoil is more directly rearward.
I can see how the slick hard-top board would accentuate lateral recoil movement if you're not using proper form.