SCOPE BLOCKS

Mount screws are included in all block prices.

Scope blocks are available in many configurations and heights.  The list below shows the more common, in-stock items.

Blocks are unhardened, black-oxide finished, and usable interchangeably for either round or octagonal barrels, unless otherwise specified. 

Hole spacing is .560" front and .860" rear, unless noted.

Prices are for individual blocks, except for Springfield and Mann-Neidner blocks which are priced as a set.

 

Please note that this product line is all directed towards the 60° dovetail, external-adjustment type of scopes (including Redfield 3200).

We do not carry any products for the "modern" Weaver or Picatinny sort of mounts.

 

PLEASE READ - We are not familiar with every possible combination of rifles and sights or scopes being mounted on them.

When we have information that we believe is correct, we're glad to pass it along.  If we don't know, we'll just say so!

There are a lot of shooters and shooting forums where the information you are seeking may (or may not!) be found.

Over their years, rifles and scopes may have been modified and/or abused. We provide industry-standard blocks and mounts,

but we are not responsible for "it doesn't fit" or "it shoots too high" or "the holes are stripped out", etc.

In addition, we have encountered bent and/or non-concentric barrels, and crooked or damaged optics,

which may result in our recommendations not being functional in those circumstances. 

If time permits (meaning not right away), we'd like to compile a list giving known rifle/block information, and post it here.

We have many old Unertl and Lyman base charts for reference - including info that is confusing, contradictory, out-of-date, or just plain wrong!

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Additional technical scope block information...

We certainly do not claim to know everything in this field, but with experience, many trends have become visible.  The following information is provided, but is open for correction or rebuttal!

Scope blocks are also called scope bases.  "Base" seems to be the older term.  Avoid using the word "mount" when talking about scopes or scope blocks!  That can be either the base (block) OR the scope ring, and this causes confusion.  (A sight "mount" is correct terminology, but note - in that case - it is not a scope mount.)

Traditional scope blocks often seem to be described as either "3/8 inch wide" or "1/2 inch wide."  In fact they are neither, although 1/2" is close.  Original Unertl ring dovetails generally measure .494" to a theoretical sharp corner.  This matches the older Winchester A5 scope ring dimensions.  MVA has told us that they cut their rings to .484" to a sharp corner, which is slightly smaller.  It's a theoretical number because due to tip wear of the dovetail cutter, a perfectly sharp inside corner on the ring is almost never achieved.  Thus if the block has a perfectly sharp corner, it is not a good situation - it would hang up on that small non-sharp inside corner of the ring.  Additionally, because these "corners" may not actually exist (either in the ring or on the block), measuring an existing part by going across the corners may not give a truly useful dimension.

The solution for these issues is two things.  First, the scope block width must be slightly narrower than the ring that it's intended to fit.  And second, the sharp corner of the block should be knocked off.  The standard blocks we make are targeted to .482" across the sharp corner.  But the actual top width will be .465", which gives an intentional small flat, allowing for non-sharp-cornered rings or even dirt in the corners.  It also makes the edge must less susceptible to damage.

Hole spacings for scope blocks are mostly standardized (although slightly odd) dimensions.  Since about 1920 or so, they seem to have been set at .560" front and .860" rear, with holes tapped 6-48.  Sometimes the .560" is .562" - I have old charts which show both.  Realistically that .002" difference is not significant.  There are numerous exceptions to these rules, however.  Older original Stevens rifles (pre-Model 414 rifles) were often drilled at .700" front and .825" rear, with 5-40 holes.  I have encountered a handful of rifles where the rear holes are spaced .875" (7/8") rather than .860".  (In fact, a tape-measure examination of .860"-spaced holes may make you think they are spaced at 7/8", which is only rarely true.)  Sometimes rifles have been drilled for Weaver-type mounts, and then the holes may be spaced either .500" or .504".  Remington 40X and 700-series rifles have a spacing on the rear ring of .600".  Remington 513T factory holes are not 6-48; they are 6-44's.  Kimber 82G has a front sight (at the muzzle) hole spacing of .500".

The scope block heights we provide are "nominal" dimensions, and the blocks will actually measure .002-.005" lower, when measured to a flat surface.  When placed on a round barrel, they will sit .005-.020" lower.

Regarding screws for scope blocks - they are made to lengths which provide adequate engagement.  It is possible that they may be too long for some applications, and will need to be shortened by filing or sanding.  It is assumed that if you are engaged in the firearms field, either as a hobby or a business, that you will not find screw-shortening to be difficult.  We do not make or offer specific odd-height screws.

A common but understandable misconception exists about how scope blocks are made here.  We do not have or make "lengths" of dovetail-shaped stock, from which we cut off the necessary pieces.  Consequently we cannot offer any "lengths" of scope block stock.

Thanks for reading!

Standard mounts vs. Posa mounts - how to tell the difference...

The mount and blocks on the left of the picture are standard Unertl mounts.

    - The mount is not split - it's solid all the way around.

    - The clamping thumbnut has a cup-shaped end, and is of one diameter.

    - The clamping nut pushes against one side of the block.

    - The block has a shallow crescent cut (also called a thumbnail or smiley cut).

The parts to the right are the Unertl "Posa" style.

    - The mount is split or saw-cut through and squeezes onto the block.

    - The thumbnut is square-ended and has two different diameters.

    - The nut pulls the mount together and does not and should not bottom out in the locking cut.

    - The block has a much deeper square-bottomed cut.

Redfield 3200 scopes can use a standard block for the rimfire mount, but require a

Posa-type block for the "big-bore" mount.  The only difference is the clamp screw itself.

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Standard

Standard blocks are available in heights of 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 5/8", 3/4", and 1".  The base has a slight concavity which allows them to mount on either a round or an octagonal barrel.  Heights are measured from a flat surface.  They will sit .005" to .018" lower on a round barrel.  They have the Lyman/Unertl crescent on one side and the Winchester dimple on the other.

Price: $23.50 each; 5/8" and taller $26.80 each

Flat-bottom

Flat-bottom blocks are specifically for mounting on an octagonal barrel.  They may "rock" on old draw-filed barrels; in that case, use the standard blocks (above).  Heights available are: 3/16", 1/4", 5/16", and 3/8". 

Price: $23.50 each

Posa

Posa blocks are for use with Unertl Posa-mount rings.  They are available either Posa/Lyman combination or Posa only (limited supply). They can also be used with the Redfield 3200 "big bore" rings.  Heights available are: 3/16", 1/4", 5/16", 3/8", 1/2", 5/8" and 3/4".  Available color-cased also.

Price: $23.50 each black, $27.90 each color-cased.

5/8" and 3/4" high are $26.80 each - black only.

Color-cased

Color-cased blocks are available in several configurations, including standard, Posa/Lyman and flat-bottom.  Heights available are: 3/16", 1/4", 5/16", and 3/8".  Flat-bottom are 3/16" and 1/4" heights only.

Price: $27.90 each

Stainless Steel

Stainless steel blocks are available either in standard or Posa/Lyman configurations.  Heights available are: 3/16", 1/4", and 5/16".  Note - these are not commonly used, and our stock availability can be limited or sporadic.

Price: $29.30 each; additional stainless screws are $2.60 each

Fecker

Blocks for Fecker mounts are slightly narrower than standard.  (Lyman and Unertl scopes will fit Fecker blocks, but Fecker scopes may not fit standard blocks).  Heights available are: 3/16", 1/4", and 5/16". 

Price: $23.50 each 

1903 Springfield

These blocks duplicate the blocks provided on 1903 Springfield rifles.  Also available in Posa configuration.  Either color-cased or black finish. 

Also on hand - heights that are .100 or .200 taller than the standard.  This allows for low-height scopes such as the Lyman to clear the bolt handle.  (Standard height '03 blocks are .230" or .235" rear and .470" or .475" front, measured to the top of the radius.)

Note - a lot of questions have arisen about using "Springfield" blocks or Unertl O & E blocks.  Functionally they are identical.  My understanding (and I am NOT an '03 expert) is that the "Springfield" blocks are the style that would have been provided by the armory, and that the O & E (Unertl-made) is what Unertl would have provided with their scopes if intended for an '03 rifle.  I have seen O & E marked blocks both square-ended, or somewhat rounded, like the "Springfield" ones.  Adding to the confusion, the opinions about whether color-cased or black finish is correct, and for exactly what era, seem to be all over the map.

Price: $58.00 per set

Stevens

These blocks are specifically for Stevens scopes.  They have the original-style V-shaped locking groove, and are available with either Stevens holes (for 5-40 screws, .700" and .825" spacing) or with standard holes.   They are also available flat-bottomed.  Heights are 3/16" and 1/4".

Price: $23.50 each 

-70 series

These are the front blocks used on the Winchester Model 70 target rifles, with the 1.750" hole spacing.  Heights are as follows... A-70 - .170";  B-70 - .230";  C-70 - .315";  LC-70 - .370".

Also available in Posa configuration.

Price: $27.90 each

Mann-Neidner blocks

Tapered blocks for Mann-Neidner mounts, intended to tighten on recoil.  They are specifically for use on '03 Springfield rifles.

New for 2016 - color-cased finish.

Price: $69.00 per set

Mann-Neidner scope ring base blanks

Tapered dovetail blank bases, for making your own Mann-Neidner scope rings.  They have been left about 1/4" longer than finished length, so they can be matched to the tapered blocks being used and cut to length appropriately.  In the white only.  Limited quantities.

Price: $49.50 per set

Cross-dovetail blocks

Meant to go into a standard 3/8" x 60° barrel dovetail.  The lower ones are either 3/16" or 1/4" high.  The higher ones are duplicates of the Unertl BK, K and KK blocks - .365", .420", and .470" respectively.  Provided with the brass set screw.  I have some that are intentionally .005" larger, to be filed to fit.

Price: $30.80 each

Vaver blocks etc.

These blocks are for Vaver front sights.  They are available either for the sights with the little pointy clamp screw, or for the ones that use the side clamp ring.  Heights are .100" or 3/16".  The .100" high blocks require special low-head screws.  The clamp rings are also available.

Blocks - $23.50 each

Screws (separately) - $2.40 each

Clamp ring - $5.50

Blanks

We have many blank, undrilled blocks on hand, already black finished.   Heights available are 3/16", 1/4", 5/16", and 3/8".

Price: $23.50 each.  Note - screws are included even though the blocks are undrilled

Screws

Screws are available for all block heights.  Standard thread is 6-48.  Stevens screws are often 5-40.  But don't worry if your rifle has different tapped holes - I currently have screws in sizes of 5-48, 5-40, 8-36 and 10-36 (limited height selection), and 6-32, 6-40, 6-44, 8-32, 8-40, and 10-32 (a11 heights up to 3/8").

Price: $2.40 each; Stainless $2.60 each

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