bOSS® - Browning

bOSS
®
owner’s manual
BOSS ® O w n e r ’ s Ma n u a l
( Ba l l i s t i c O p t i m i z i n g S h o o t i n g Sy s t e m )
Important: Carefully read this entire owner’s manual
before using your new BOSS-EquipPed Browning rifle,
and save it for future reference.
Record the following information for future reference:
Browning Model_________________________________
Serial Number___________________________________
Y o u A r e R e s p o n s i b l e F o r F i r e a r m s Saf e t y
The instructions in this owner’s manual are specific to the BOSS®
System installed on your new A-Bolt or BAR rifle. You must read and
understand the cautions and proper handling procedures outlined in
this owner’s manual, and in the owner’s manual received with your
rifle before using your new BOSS-equipped rifle. If you are missing the
owner’s manual for your rifle, we will send you a free replacement
upon request. You can also visit our website at browning.com as many
of our owner’s manuals are posted online.
Caliber_________________________________________
Purchase Price___________________________________
Purchased From__________________________________
Date of Purchase_________________________________
THE THREADING ON the BARREL IS FOR BROWNING BOSS COMPONENTS
ONLY. DO NOT INSTALL ANY OTHER DEVICE ONTO THE BROWNING BOSS
BARREL. DO NOT INSTALL THE BOSS DEVICE ON ANY RIFLE WHICH IS NOT
DESIGNED AND FITTED FOR THE BOSS BY BROWNING. DOING SO MAY
CAUSE SERIOUS INJURY OR DEATH TO YOURSELF OR OTHERS, and cause
damage to your rifle.
G e n e r a l O p e r at i o n
The BOSS (Ballistic Optimizing Shooting System) allows you to
fine-tune for improved accuracy by modifying the vibrations of
your rifle’s barrel using an adjustable weight system.
sweet spot charts
Every time a rifle is fired, barrel vibrations are set in motion. These
vibrations occur in all directions, even back and forth along the axis
of the barrel. Our research has confirmed that barrel vibrations are
the primary cause of inaccuracy. Barrel vibrations are influenced by
many factors such as bullet type, bullet weight, primers, powders
and barrel configurations. With the BOSS system, no longer will you
need to try a variety of ammunition to obtain acceptable accuracy.
You can quickly and easily tune your rifle to get the optimum accuracy
for all available factory loads by adjusting the BOSS system to modify
barrel vibrations.
Sweet Spot charts for your BOSS-equipped rifle are available at
browning.com or by calling (800) 333-3288.
The BOSS adjusts the timing of barrel vibrations so the bullet
consistently leaves the rifle’s muzzle at the most advantageous time.
1
Figure 1
Micro-Adjustable
Lock Nut
Figure 2
Micro-Adjustable
Lock Nut
Weight
Body
Micrometer Adjustment Ring
BOSS (with muzzle brake)
Body
Micrometer Adjustment Ring
BOSS-CR (conventional recoil)
Once the BOSS is adjusted to this “Sweet Spot” for a given
ammunition, your rifle will consistently deliver extraordinarily
tight groups. In fact, BOSS-equipped rifles in a variety of calibers
are capable of producing 100 yard, one-hole groups with precision
ammunition. The smallest three-shot group obtained during the
BOSS development measured an incredible .051" at 100 yards,
using factory loaded ammunition.
When adjusted to its Sweet Spot, the BOSS will compensate for slight
deviations in ammunition velocity. However, the BOSS will not
compensate for poor shooting or flyers caused by low quality bullets
and ammunition.
Note: To obtain the highest level of accuracy from your rifle, it
is recommended that the rifle bore be cleaned after firing 12-15
rounds. See “Cleaning the Rifle Bore” on page 10 in this owner's
manual for cleaning procedures.
M u z z l e B r a k e F e at u r e
The BOSS is available in two versions, the muzzle brake version
(Figure 1) and the CR (conventional recoil) version (Figure 2).
THE BOSS with RECOIL REDUCING MUZZLE BRAKE PROVIDES
SUBSTANTIALly INCREASED NOISE and MUZZLE BLAST. ALWAYS WEAR
HEARING PROTECTION TO PREVENT HEARING LOSS OR DAMAGE.
2
The unique exhaust port pattern on the BOSS with muzzle brake
provides considerable recoil reduction. Recoil reduction of the BOSS
ranges from 30% to 50% — depending on caliber, weight of rifle, etc.
You will experience an increase in noise and concussion (muzzle blast)
when a BOSS-equipped rifle is fired. Hearing protectors (shooting ear
plugs or muffs) should always be worn to guard against hearing
damage when shooting a BOSS-equipped rifle. Wear shooting glasses
to protect your eyes from flying particles. Always keep a safe distance
between the muzzle of your firearm and any persons nearby, as muzzle
blast, debris and ejecting shells could inflict serious injury.
BOSS S p e c i f i c a t i o n s
The BOSS body length is 2" for all calibers. The size of the gas vent
ports and port pattern is the same for all calibers. The size of the bullet
exit opening is the same for all calibers except for the 338 Win. Mag.
and 375 H&H. The thread system for the 338 Win. Mag. and the
375 H&H is different from other calibers to rule out the possibility of
accidentally switching components and creating an unsafe combination.
Do not attempt to interchange these systems. Use only the BOSS
intended for your rifle.
The BOSS consists of a micro-adjustable lock nut and body
(Figures 1 and 2). The weight is affixed to the body with LOCTITE®
thread locking compound. The micro-adjustable lock nut has a
micrometer adjustment ring. To obtain the utmost accuracy from your
BOSS-equipped rifle, it is very important that the micro-adjustable
lock nut and body are always tight.
The Sweet Spot
Precision accuracy from the BOSS system is achieved by calibrating
your rifle caliber and ammunition from a prescribed Sweet Spot
setting found on the BOSS Sweet Spot chart. The chart is available
separately from this owner’s manual. If you do not have a Sweet Spot
chart, call (800) 333-3288 to request one. You can also find Sweet Spot
information at browning.com.
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The chart lists average, or suggested, Sweet Spot settings. These
settings were determined through extensive testing by our Research
and Development staff. Sweet Spots may vary between rifles of
identical specifications with given ammunition. Even one quarter of a
turn away from the Sweet Spot can cause a group to spread out as
much as one inch or more. We suggest you use our listed Sweet Spot
settings as a starting point in determining the exact Sweet Spot setting
for your particular rifle and make changes accordingly.
Important: Any change to the BOSS settings may slightly alter
your rifles point of impact. It is recommended you set the BOSS
Sweet Spot setting before sighting in your rifle for windage and
elevation. The BOSS was tested in full turn, ½ and ¼ turn increments.
Tighter groups may be achieved with the BOSS tested in other
positions. On the Sweet Spot chart, Sweet Spots are listed by both
ammunition and rifle model. Settings not listed either do not apply
or are for ammunition not yet tested.
Preliminary Adjustments
Before performing BOSS calibration adjustments to your rifle,
MAKE SURE YOUR rifle IS completely UNLOADED. Remove the
magazine, check the action and chamber for cartridges. Keep
the muzzle pointed in a safe direction. Failure to follow these
warnings could result in serious injury or death.
Before setting your Sweet Spot,
it is important that your BOSS
Figure 3
be calibrated with the barrel
The BOSS must be calibrated so the ”0“ on the
(Figure 3). This will ensure that
BOSS lines up with the indent mark on the barrel.
your rifle is consistent with
those tested by our Research
and Development staff when
the BOSS Sweet Spots were
initially determined.
4
Figure 4
Figure 5
The micro-adjustable lock nut must be
bottomed out on the barrel threads.
Rotate the micrometer adjustment ring.
To find out if your BOSS needs to be recalibrated, loosen the
micro-adjustable lock nut and turn it until it bottoms out on the
threads of the barrel — or will not loosen any further (Figure 4).
If your BOSS is calibrated, the “0” mark on the micrometer adjustment
ring will line up with the longitudinal index mark on the barrel as
shown in Figure 4. If the “0” mark is not aligned with the longitudinal
index mark, you will need to calibrate your BOSS.
To calibrate the BOSS, move the micrometer adjustment ring on
the bottom of the micro-adjustable lock nut so the “0” on the split
ring is aligned with the longitudinal index mark on the barrel. To
adjust the micrometer adjustment ring, insert your fingernail or a
small pointed object in the split of the ring and rotate the ring until
the “0” mark on the split ring is aligned with the longitudinal index
mark on the barrel (Figure 5).
IMPORTANT: It is not necessary to calibrate your BOSS with each
change in Sweet Spot settings. However, you should check the BOSS
periodically to assure proper alignment.
Setting Your Rifle’s Sweet Spot
Before SETTING THE Sweet Spot to YOUR RIFLE, MAKE SURE YOUR
rifle IS completely UNLOADED. Remove the magazine, check the
action and chamber for cartridges. Keep the muzzle pointed in
a safe direction. Failure to follow these warnings could
result in serious injury or death.
5
Figure 6
Full-turn Sweet Spot increments.
Figure 7
1⁄10
turn Sweet Spot increments.
Full-turn Sweet Spot settings or graduations are numbered 1-10 and
inscribed on the barrel of your rifle (Figure 6). Smaller 1⁄10 turn
increments are inscribed on the micrometer adjustment ring
(Figure 7). To set the Sweet Spot, the micro-adjustable lock nut is
turned either clockwise or counterclockwise until it is aligned with
the desired Sweet Spot number inscribed on your rifle’s barrel. One
full revolution of the micro-adjustable lock nut indicates one full
change in setting, or one index mark on the barrel. 1⁄10 turn increments
are set by rotating the micro-adjustable lock nut until the desired
setting lines up with the index mark on the barrel.
IMPORTANT: When adjusting the Sweet Spot, make sure you grip
the knurled surface of the lock nut. The knurled portion of the
micro-adjustable lock nut and micrometer adjustment ring must
rotate together to ensure a precise Sweet Spot setting and to retain
proper calibration.
E X A MPLE 1
1Suppose you have an A-Bolt rifle in 270 Win. caliber and are
sighting in with 150 grain cartridges. Referring to the Sweet Spot
chart, you will find the average Sweet Spot to be 6.0 for an A-Bolt
in 270 Win. with 150 grain ammunition.
2After having made sure your BOSS is calibrated properly on the
barrel, rotate the micro-adjustable lock nut counterclockwise six full
revolutions. The edge of the micrometer adjustment ring should
line up, or rest, on the marking for 6.0 on the barrel of the rifle.
6
Figure 8
Example 1: Sweet Spot set at 6.0.
Figure 9
Tighten the BOSS so it is secure.
3Since the Sweet Spot setting is listed at 6.0, the 0 inscribed on the
micrometer adjustment ring should line up with the index mark
or longitudinal line on the barrel (Figure 8).
4Tighten the body of the BOSS so it is secure against the
micro-adjustable lock nut. Use the special wrench supplied with
your rifle. On the muzzle brake BOSS insert the wrench through
one end of an exhaust port and out through another. It is
recommended to insert the wrench through the smallest set of
ports possible. On the BOSS CR insert the wrench through a port
on the end of the BOSS and out through another (Figure 9). Turn
clockwise until the body and micro-adjustable lock nut are tight.
Be sure to REMOVE THE WRENCH FROM THE BOSS EXHAUST PortS
BEFORE FIRING YOUR RIFLE. FAILURE TO DO SO MAY CAUSE SERIOUS
INJURY OR DEATH TO YOURSELF OR OTHERS, and cause damage to
your rifle.
E X A MPLE 2
1Suppose you have a 243 Win. BAR rifle and are using 100 grain
cartridges. Referring to the Sweet Spot chart, you will find the
average Sweet Spot to be 2.5.
2Calibrate your BOSS and rotate the micro-adjustable lock nut
counterclockwise until the edge of the micrometer adjustment
ring lines up, or rests, on the marking for 2.0 on the barrel.
7
3Since the Sweet Spot is listed
as 2.5, the 5 inscribed on the
micrometer adjustment ring
should line up with the index
mark or vertical line on the
barrel (Figure 10).
Figure 10
4Using the special wrench,
Example 2: Sweet Spot set at 2.5.
tighten the body of the BOSS
so it is secure against the lock
nut as explained previously.
Your BOSS system is now calibrated
for 100 grain ammunition using a 243 Win. BAR rifle.
More Precise Adjustments
If you desire to further experiment and possibly obtain even tighter
groupings, turn the micro-adjustable lock nut ¼ of a turn clockwise
and fire your rifle at a safe target. If the group opens up (gets larger),
turn the micro-adjustable lock nut counterclockwise and sight in at
different ¼ turns until you are satisfied with your groupings. Sweet
Spot settings may vary between rifles of identical specifications with
a given ammunition. As in any sighting-in process, the best results
are obtained through systematic trial and error. You may need to
retune the BOSS should you decide to shoot ammunition of
different brands, lots and/or types.
Be sure to keep a detailed record of your rifle’s Sweet Spot
settings, especially if you use your rifle for different game and
shoot different loads.
WHEN ADJUSTING THE Sweet Spot, NEVER SET THE BOSS BEYOND
THE 10 SETTING. The BOSS could become loose, misaligned
or disengaged when firing the rifle resulting in sERIOUS
INJURY OR DEATH TO YOURSELF OR OTHERS, and cause damage
to your rifle.
8
Figure 12
Figure 11
Trigger Guard Screw
Barrel Mounting Screw
BAR Forearm Locking Screw
IMPORTANT: Each time you set the Sweet Spot, the body of the
BOSS must be tight against the micro-adjustable lock nut. Failure to
keep the components tightly locked will adversely affect accuracy.
IMPORTANT: The barrel mounting screw and trigger guard screw on
the A-Bolt should also be fully tightened (Figure 11). If the barrel
mounting screw and trigger guard screw are loose on your A-Bolt,
tighten the barrel mounting screw before tightening the trigger guard
screw. On the BAR, the forearm locking screw should be kept fully
tightened (Figure 12) to obtain, and retain, the best possible accuracy
from your rifle.
Ny l o n L o c k i n g D e v i c e
A strip of nylon in the threaded portion of the barrel helps keep the
BOSS body properly positioned at the Sweet Spot setting. This locking
device keeps the components tight to the barrel, which is essential for
optimum accuracy (Figure 13).
The nylon may become worn with Figure 13
prolonged use and may require
Nylon Locking Device
replacement. Replacement nylon
locks are available from the
Browning Parts Department in
Arnold, Missouri.
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Ca r e o f y o u r BOSS - e q u i p p e d R i f l e
IMPORTANT: The BOSS is a precision instrument. In order for the
BOSS system to operate effectively, it is extremely important that your
rifle remains in its original purchase condition. It is necessary for the
barrel to remain free-floating and the action properly bedded.
The above statement holds true either for the A-Bolt or BAR. To check
for adequate barrel clearance, it is recommended that a piece of paper,
folded once, be able to pass between the barrel and stock without any
interference. If the barrel is not free-floating, take your rifle to a
qualified gunsmith, a local recommended Browning Firearms Service
Center or send it to the Browning Service Department in Arnold,
Missouri. Special rubber bedding in the recoil lug area of your
BOSS-equipped A-Bolt rifle is installed at the factory and aids greatly
in improving accuracy. (Rubber bedding is not needed for the BAR.)
If you have any modifications made to your stock, make sure the
rubber bedding has not been altered. If the rubber bedding on your
rifle has been modified, send your rifle to the Browning Service
Department in Arnold, Missouri.
Cleaning the Bore
To maintain the utmost accuracy from your BOSS-equipped rifle,
or any rifle, extensive testing has proven that the rifle bore must
be cleaned after every 12 to 15 rounds.
BEFORE PERFORMING CLEANING PROCEDURES, make sure the rifle is
Completely Unloaded. Remove the magazine, check the action
and chamber for cartridges. Keep the muzzle pointed in a safe
direction. Failure to follow these warnings could result in
serious injury or death.
WEAR EYE PROTECTION WHEN DISASSEMBLING AND CLEANING YOUR
rifle TO PREVENT SOLVENTS OR OTHER AGENTS FROM CONTACTING
YOUR EYES, resulting in injury.
10
Keep all ammunition away from the cleaning area. Never test
the mechanical function of your rifle with live ammunition.
Failure to follow these warnings could result in serious
injury or death.
MOST SOLVENTS ARE HIGHLY FLAMMABLE. WEAR EYE PROTECTION and
practice APPROPRIATE SAFETY MEASURES WHEN WORKING WITH
SOLVENTS to avoid serious injury.
We highly recommend that your rifle be cleaned with the BOSS
installed on your barrel. On the A-Bolt, remove the bolt and clean the
rifle from the breech end. The BAR, by design, must be cleaned from
the muzzle end. Use a rod guide and extra care when cleaning to avoid
damaging the muzzle crown.
Modern cartridge jackets are made mainly of copper and zinc. These
metals glide easily and prolong barrel life; however, residues from
copper and zinc stick to the barrel and require more frequent cleaning.
As top benchrest shooters have known for decades, copper solvent is
the key to cleaning a barrel for optimum accuracy. The recommended
cleaning procedure is as follows:
1Clean the bore with a good powder solvent to remove all traces
of powder residue. Performing this step before the application
of a copper solvent will prevent the bore from refouling with
copper so readily.
2Swab the bore with a good copper solvent using the
manufacturer’s recommended procedures. After neutralizing
the solvent, generally with oil, it is important to swab the
bore dry to reduce copper buildup.
NOTICE! DO NOT USE SOLVENTS OF DIFFERENT MANUFACTURERS
CONCURRENTLY. A CHEMICAL REACTION MAY RESULT THAT WILL
CORRODE EVEN STAINLESS STEEL BARRELS. IT IS IMPORTANT TO
FOLLOW THE MANUFACTURER’S RECOMMENDATIONS EXACTLY.
11
3If necessary, the BOSS may be removed to facilitate cleaning
your rifle.
NOTICE! WHEN CLEANING THE BAR WITH THE BOSS REMOVED, THE
PLASTIC CAP (CROWN AND ACCURACY PRESERVER) PROVIDED WITH
THE RIFLE SHOULD ALWAYS BE USED TO PROTECT THE MUZZLE
CROWN. ALWAYS MAKE SURE THE CAP USED MATCHES THE CALIBER
OF THE RIFLE BEING CLEANED. THE CALIBER IS MARKED ON THE
END OF THE CAP.
Clean the BOSS by unscrewing the body and micro-adjustable
lock nut from the rifle. With the components disassembled, wipe
each component with oil. Browning Oil is excellent for this
application. Lightly oil all threads and make sure the exhaust
ports are free of obstructions.
NOTICE! REMEMBER TO REMOVE THE PLASTIC CAP WHEN
REASSEMBLING THE BOSS ON THE BAR.
4Reassemble your BOSS by screwing on the micro-adjustable lock
nut and then the BOSS body. After taking apart the BOSS, it will
be necessary to reset the Sweet Spot.
Service or repair
If your firearm should require service or repairs, we suggest you first
contact a local recommended Browning Firearms Service Center.
To locate a service center visit browning.com, contact our Customer
Service Department or your Browning firearms dealer for the address
of the Service Center nearest you. Otherwise, you may send your
firearm directly to our Service Department in Arnold, Missouri.
Parts listings, Firearm Service Center lists, service procedures, service/
repair form and general product information are also found on the
internet at browning.com. For technical questions about your firearm
or service, contact:
United States customers:
Browning Firearm Status and
Technical Service
One Browning Place
Arnold, MO 63010-9406
Phone: (800) 322-4626
Canadian customers:
Browning Canada Sports Ltd/Ltée
5583 Chemin St-François
St-Laurent, Quebec H4S 1W6
Phone: (514) 333-7261
When returning your firearm for servicing, you must do the following:
1 Be sure it is completely unloaded.
MAKE CERTAIN ALL CLEANING PATCHES ARE REMOVED FROM THE
BARREL AND EXHAUST PortS IN THE BODY OF THE BOSS BEFORE
FIRING YOUR RIFLE. FAILURE TO DO SO MAY CAUSE SERIOUS
INJURY OR DEATH TO YOURSELF OR OTHERS, and cause damage
to your rifle.
5After cleaning the bore, it is recommended two fouling shots
be fired before firing for extreme accuracy. Additionally, it is
recommended the rifle be allowed to cool after every three shots.
2 Remove the scope or other optics.
3 Package it securely in a cardboard container.
4 Enclose the service/repair form available at browning.com or a
letter that clearly describes the trouble experienced, the
ammunition used and the repairs desired. Also include your name
and a daytime phone number where you can be reached.
5 If convenient, send a copy of the service/repair form or letter
to us separately.
6 Never return ammunition with your firearm. It is against postal
and most commerce regulations.
12
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browning.com
BROWNING US: Morgan, Utah 84050-9326
BROWNING CANADA: Browning Canada Sports Ltd/Ltée, St-Laurent, Quebec, H4S 1W6
BROWNING INTL: Parc Industriel des Hauts-Sarts, B-4040 Herstal, Belgium
A01101/11048