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Precision CNC Machining

As a service to a valued customer, David Coggin is helping Bob get the word out on his new product
until he gets his own web page up and running.

  Original Bob Sled 
for the
AR-15   AR-10  Tikka

Now Available... AR-10 Match Length Bob Sled

New Through-the-Trigger Guard Bolt Release now Available

TGBR25 AR-15 Through-the-Trigger Guard Bolt Release.
OBS10 Single loader-Short-Space Gun.
OBS20 Single Loader-Tall-Service Rifle.

Original Bob Sled 

AR-15 Single shot loading device.

  • Operates and feels like a standard 20 round magazine.
    Made from solid Delrin.
  • The loading channel perfectly aligns the round to enter the chamber.
  • The plunger automatically activates the bolt stop and holds the bolt open ready for the next round to be loaded.
  • Excellent for standing and slow fire competition.

Brownells sells the AR-15 Bob Sleds.

Sinclair International sells the AR-15 Bob Sleds.

Sells the Original Bob Sleds for AR-15, AR-10, and SR-25/DPMS-LR308

Sells the Original Bob Sled.

Champion's Choice Sells the Original Bob Sleds

Sells the Original Bob Sleds
Sells the Original Bob Sleds for AR-15

Sells the Original Bob Sleds
Shooter Ready? Long Range Shooting Simulation Game & Custom Firearms.

Bob has designed the Original Bob Sled for AR-15 rifles. It is a magazine that holds no rounds. Its purpose is to allow the loading and firing a single rounds during competition, at the benchrest, or out varmint shooting. The OBS is machined from a single piece of Black DELRIN.

Here is how it works: The OBS is inserted instead of a magazine. The bolt is opened. The built in plunger on the OBS trips the bolt stop and holds the bolt open. A single round is then placed in the bolt port and allowed to rest in the channel of the OBS. The bolt release button is pressed and a single round is loaded. Once that round is fired, the action cycles normally and the OBS plunger trips the lever to hold the bolt open. This is a very smooth operation for slow fire.

The advantages of the Original Bob Sled are:

The advantages for Competition:

Delrin is a very durable material and is not affected by gun cleaning solvents. You can use a cloth and WD-40 to clean and shine the OBS.
Delrin® (Polyoxymethylene)
Properties of Delrin
Delrin Material Data Sheet

David Coggin has machined a number of these AR-15 Original Bob Sleds.

Left side of the Original Bob Sled made from DELRIN


Rear view of the OBS showing the loading channel and the bolt stop plunger.


The OBS may be shortened to be flush with the magazine port by sawing it off at the "White Line".

Shortened models are also available.
Here is one of the shortened models.
The bolt-lock plunger is lubricated for life with "The Ultimate Weapons Lubricant" MILITEC®-1
Looking from the rear of the magazine, the left lip is chamfered so a round will
not ride on top of it and cause a "Stove Pipe" jam with a live round.

Designed for the SR-25/DPMS-LR308 
Stoner SR-25 Semi-Auto Rifles & DPMS Long Range .308 Semi-Auto Rifles

AR Carrier Hanging Up Rare, but here is some info on it.

Here is a view of the Original Bob Sled installed in an AR-15. Note the prototype Through-the-Trigger Guard
Bolt Release extension that will release the bolt by pushing the lever through the trigger guard. This is now
a production item.

The Through-the-Trigger Guard Bolt Release is now available.

Bolt Release Lever Installation instructions

                The new roll pin is flared at the engraving end to retain the lever after installation.
                (Hint) Mask off your lower so as not to scratch if punch slips!

Step 2     Drive the existing roll pin out aft to the buttstock, leaving 3/32 punch in place.

Step 3     Drive New Pin and Lever WITH SCOTCH TAPE ATTACHED Forward until
               New Roll Pin just protrudes from forward edge of attachment point.
               STOP and remove tape. Lever has a clearance hole and floats around new pin.
               Your New lever is designed to require a definite motion to release the bolt.
               This is for safety purposes, i.e. a light bump will not close the bolt..!
               Thank You !

  Original Bob Sled 



The Tikka M595 (made by Sako) is a match grade hi-power competition rifle. It is a bolt action that feeds from a single stack, centerline feed magazine. The barrel is free-floated and the stock comes with a hand stop rail as standard equipment.

Extra magazines are $60 each, so not having to purchase an extra magazine will more than offset the cost of the Original Bob Sled -TIKKA- Version.

The sled is made of white Delrin for safety, (easier to see when it is installed compared to the black base of the actual magazine) and will not scratch or damage your stock and is basically indestructible. The OBS shape matches the actual magazine and fits flush with the bottom of the stock. When the magazine release button is pushed , the Tikka OBS "pops out" using the same plunger as an original magazine.

The OBS -TIKKA- works in both .308 and .223 versions of this fine rifle.

Right side view of the Tikka OBS.


View with the muzzle to the left.

View with the buttstock to the right.

AR-10 Match Length Bob Sled

David Coggin has machined a number of these Original Bob Sled for the AR-15, AR-10, and Tikka rifles. 

Excerpt from 2003 CMP Competition Rules 7th edition.

7.2.3 U.S. Rifle, Caliber 5.56mm, M16
The rifle must be a rifle that was
issued by the
U.S. Armed Forces or a commercial rifle of the
same type and caliber. M16 rifles must be
chambered for the 5.56mm cartridge and comply
with the following specific requirements

(1) Modification to make automatic fire impossible
without removing, replacing or altering parts is

(2) Magazines of the standard service 20 or 30
round box magazine dimensions must be
attached during the firing of all courses and in
all positions. A dummy magazine with a ramp
for single shot loading may be used, provided
this magazine has the same external configuration 
and dimensions as the standard
service 20 round magazine.

AR15.com Ammunition FAQ

The Competitive AR15

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Contact us for a free estimate:
David Coggin
1318 Calle de las Granvas
Livermore Ca 94551
(925) 519-9795
FAX (925) 960 1770

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