Wanted: Sporter forearm benchrest adapter

[Brians356]

Saran wrap. bondo and a 12" peice of aluminum channel. Wrap forearm in one layer of Saran wrap, mix bondo, put bondo in channel ,place forearm in bondo, fifeteen minutes, Forearm adapter. Randy

Thanks. Yes, that's my style as well, done similar things many times using epoxy. However, it only fits properly on that one rifle.

 

[Brians356]

Epilogue:

I purchased a used Sinclair Forend Benchrest Adapter from "tenring".

Needing additional mounting screws for different rifles' swivel stud receivers, I contacted Sinclair tech support on the phone, and they are sending me a package of the three different attachment screws, plus some extra stick-on rubber buffers, gratis.

I told the rep. I would gladly pay for them, or at least the shipping, but he wouldn't hear of it, so I promised him I would spread the word of Sinclair's service and generosity. Done.

 

[22BRGUY]

Have a close friend machinist that is in the process of making some off of the Sinclair design but will use a different type of "plastic" instead of derlin. He's very good at what he does and hope to see one from him soon.

 

[Brians356]

Have a close friend machinist that is in the process of making some off of the Sinclair design but will use a different type of "plastic" instead of derlin. He's very good at what he does and hope to see one from him soon.

I haven't actually mounted mine yet, it remains to be discovered how firmly it attaches. Relying on only the single #10 machine screw seems a bit tenuous, but since Sinclair has been selling these for years or even decades, and word of mouth being what it is in the Information Age, the device must function more or less as advertised.

 

[justpassinthru]

Have a close friend machinist that is in the process of making some off of the Sinclair design but will use a different type of "plastic" instead of derlin. He's very good at what he does and hope to see one from him soon.

I haven't actually mounted mine yet, it remains to be discovered how firmly it attaches. Relying on only the single #10 machine screw seems a bit tenuous, but since Sinclair has been selling these for years or even decades, and word of mouth being what it is in the Information Age, the device must function more or less as advertised.

That one screw does seem a bit flimsy, but it's not as bad as it sounds.
When you slide each aluminum side piece in tightly against the forend, it becomes quite sturdy.
I have one on the tube forend of a AR-15 at the moment and it works great.

 

[Brians356]

That one screw does seem a bit flimsy, but it's not as bad as it sounds.
When you slide each aluminum side piece in tightly against the forend, it becomes quite sturdy.
I have one on the tube forend of a AR-15 at the moment and it works great.

Yep, I mounted it last night, it is quite firm. I put a wedge of wood under the forend tip to render it nearly parallel to the bore, otherwise the forend taper creates quite an angle which defeats the whole purpose of sitting horizontal on the front bag.

 

[justpassinthru]

That one screw does seem a bit flimsy, but it's not as bad as it sounds.
When you slide each aluminum side piece in tightly against the forend, it becomes quite sturdy.
I have one on the tube forend of a AR-15 at the moment and it works great.

Yep, I mounted it last night, it is quite firm. I put a wedge of wood under the forend tip to render it nearly parallel to the bore, otherwise the forend taper creates quite an angle which defeats the whole purpose of sitting horizontal on the front bag.

I haven't had that problem with anything I've used it on, but will keep that in mind.

 

[Brians356]

I haven't had that problem with anything I've used it on, but will keep that in mind.

This is on a Rem 700 VS w/ HS Precision stock. The forearm is fairly fat and tapers considerably near the end, and the stud is near the end, so that the front of the Sinclair adapter is hanging out into space. And without a wedge, it is angled down towards the rear considerably.

If I left it like that, the point of aim on target would move up and down an inch or so while I slid the rifle fore/aft on the front bag! And it would slide backwards on it's own if the rear bag was slick enough to not grip it.

I hope this all makes sense, I'll try to upload some pictures.

 

[justpassinthru]

Yes, it makes perfect scene.
Still though, even with that little bit of trouble, it lets you do something with your gun that you otherwise couldn't do.

 

[Brians356]

Yes, it makes perfect scene.
Still though, even with that little bit of trouble, it lets you do something with your gun that you otherwise couldn't do.

Little trouble, indeed. I took a cheap wooden clothespin and cut an inch or so off one "leg" - instant wedge. Slipping into place took and tightening it down took a few seconds. Adjusting it a bit by trial/error a minute more.

 

[22BRGUY]

As I mentioned I have a Sinclair and mounted on the forearm of an Anschutz I have. I was not really concerned much about the thing being parallel and expected it to recoil a bit up and down with recoil. To minimize that, I pressed the thumb of my trigger hand against the back of the trigger guard and used the "pinching style" trigger pull. I think it was Boyd Allen that said this might not work on heavier recoiling rifles and I can see where he's right. Anyway, just another thought for you guys to consider.
Best Wishes

 

[Brians356]

I do use the trigger guard pinch. This rifle is 223 Rem, BTW. But no matter, I need the adapter to be horizontal on the bag, so I shim it. Can't imagine anyone wanting it sloping sharply down in back, the whole idea of it is to make a narrow, sloping sporter sit there like a wide, straight benchrest stock on the bag.

 

[22BRGUY]

I do use the trigger guard pinch. This rifle is 223 Rem, BTW. But no matter, I need the adapter to be horizontal on the bag, so I shim it. Can't imagine anyone wanting it sloping sharply down in back, the whole idea of it is to make a narrow, sloping sporter sit there like a wide, straight benchrest stock on the bag.

Very true Brian but there should be some adjustment available on the rear bag to help with that or am I missing something? and unless the bottom of the buttstock is flat and parallel to the barrel, won't it still recoil up and down on firing? Maybe my mind is missing something here.

 

[Brians356]

I do use the trigger guard pinch. This rifle is 223 Rem, BTW. But no matter, I need the adapter to be horizontal on the bag, so I shim it. Can't imagine anyone wanting it sloping sharply down in back, the whole idea of it is to make a narrow, sloping sporter sit there like a wide, straight benchrest stock on the bag.

Very true Brian but there should be some adjustment available on the rear bag to help with that or am I missing something?

Yes. There is no tilt adjustment. There are only the side clamp adjustments, and the single attachment screw.

and unless the bottom of the buttstock is flat and parallel to the barrel, won't it still recoil up and down on firing? Maybe my mind is missing something here.

Well, the Sinclair device only addresses the front end of the rifle, and I am only concerned with adjusting the Sinclair. Your point about recoils is valid, but for my part I never said or implied that having the Sinclair leveled would affect recoil one way or another; in fact, I never used the word recoil at all. All I discussed was the effect on setup, stability, and aiming pre-shot.

Thanks!

 

[MFG_BOP]

Sorry, I didnt read the whole thread, but here it goes:

http://www.mwerksllc.com/plates.php

http://www.xlrindustries.com/chassis-options.html

http://www.whiddengunworks.net/trackplate.html

If you want to make one:

http://forum.accurateshooter.com/index.php?topic=3770106.0

 

[22BRGUY]

I do use the trigger guard pinch. This rifle is 223 Rem, BTW. But no matter, I need the adapter to be horizontal on the bag, so I shim it. Can't imagine anyone wanting it sloping sharply down in back, the whole idea of it is to make a narrow, sloping sporter sit there like a wide, straight benchrest stock on the bag.

Very true Brian but there should be some adjustment available on the rear bag to help with that or am I missing something?

Yes. There is no tilt adjustment. There are only the side clamp adjustments, and the single attachment screw.

and unless the bottom of the buttstock is flat and parallel to the barrel, won't it still recoil up and down on firing? Maybe my mind is missing something here.

Well, the Sinclair device only addresses the front end of the rifle, and I am only concerned with adjusting the Sinclair. Your point about recoils is valid, but for my part I never said or implied that having the Sinclair leveled would affect recoil one way or another; in fact, I never used the word recoil at all. All I discussed was the effect on setup, stability, and aiming pre-shot.

Thanks!

Thank you Brian for clarification.....so then your concern is that the flat bottom of the adapter is parallel with the rifle bore..correct?

 

[Brians356]

Thank you Brian for clarification.....so then your concern is that the flat bottom of the adapter is parallel with the rifle bore..correct?

Sure. Not absolutely parallel, that's impossible with the crude adjustment using a wedge, and it's impossible to assess true parallelism accurately anyway. But if I move the rifle fore/aft slightly on the bags, little if any shift up/down of point of aim should be from the tilt of the adapter. As you point out, there is still the sloped buttstock to deal with.

Too, if the adapter is horizontal, it won't want to fall back off the front bag when I let go of the rifle, just from gravity (again, doesn't address the same problem at the butt, but there I can use the pistol grip as a stop, plus the stock surface is not slick like the Delrin adapter, so it wants to stick in place more.)

In general, I (and I assume others) want the rifle to be as "hands off" as practical on the bags, hence the design of benchrest pedestals with mechanical elevation/windage adjustments and confining front bags supports, and the straight-line buttstocks.

Ideally, I could get the gun sitting perfectly on aim point, and only have to touch the trigger and trigger guard to fire it, but with the sporter buttstock, I will still have to manipulate the rear bag, but at least I won't have to deal with the front end once it's set up.