A lot of materials are good at stopping regular target arrows with field points.  One thing experienced bowhunters will understand is that their broadheads will not always fly and group the same as field tipped arrows.  More often than not, some considerable bow tuning will be required for good broadhead tipped arrow flight.  If your game is strictly big game bowhunting, then you might want to consider shooting broadheads during practice all year 'round.  Stopping broadhead arrows comes with a unique set of problems.

The following is a recommendation from Chuck Adams' "Complete Book of Bowhunting."  In it he describes the use of a "Sand trap" target butt.  It is a large wooden box, in a wedge shape with an open front, in which dry sand is piled and sloped, providing a superior material and back stop for extended target practice season after season.  Compared to commercially available foam target butts, the sand trap isn't all that expensive, and is constructed from common materials such as plywood, two by fours and sand.  The bigger the box, the more reinforcement on the sides and back necessary to support the sand and keep the structure from bowing out.  Over my 30 year bowhunting career, I have built over 4 of these sand traps, and I still swear by them (not at them). I haven't had to build new ones from wearing out, but I have relocated a few times.  They take some effort to build, but are well worth it as they save some frustration down the road..  There are only two disadvantages to the sand trap.  The first is that it isn't portable, and secondly, it is necessary to keep the sand covered to keep it clean and dry (keep out the cats and rain!)

The advantages are significant.   The sand lasts forever.  Good clean play-sand isn't sharp, and does not abrade arrow shafts even through years and years of target practice.  Because the sand is homogenous, it offers a superior material for consistent arrow penetration that allows for quick and accurate bare shaft bow tuning.  Starting up close, and working back systematically will determine bare shaft arrow flight and instant feedback in tuning for horizontal and vertical center shot.  It is much simpler than trying to set up a large sheet of craft paper for "paper tuning." Any deviation from straight arrow flight is captured and even exaggerated as the bare shaft arrow penetrates into the sand.  However, since the sand is sloped, it will deflect the front end of the arrow upward slightly.  Once this peculiarity is realized, it can be compensated for, as the action is consistent.  Standing very close to the sand, and releasing the arrow into the slope perpendicularly will negate this effect.  This same feature cannot be duplicated by the use of other materials that provide inconsistent resistance from previously shot holes and varying densities.  In sand, arrows are stopped within inches, and broadhead tipped arrows can be withdrawn without even the slightest effort.  The light color of sand also contrasts with the arrow in flight, important visual clues in how things are flying.   Some broadheads will not last a even a couple of shots into sand.  I don't consider this a disadvantage whatsoever.  On the contrary, it exposes the lack of structural integrity of the broadhead in question.   Although it isn't bone, resisting impact with sand is solid proof of a broadhead's durability.  Tough broadheads will last for many years of shooting into sand, and these types are the ones that should be used for hunting.  Of course, the sand will dull the blades, but these are for practice only.  Keep another set for hunting, and as always, they should be kept scary sharp!

It isn't necessary to build a sand trap opening larger than 3' x 3'.  The tradeoff of a smaller target area is that it will force the archer to perform better, or be prepared to buy more arrows.  It's added incentive for the most important aspect of good accurate shooting; concentration.  To become a good archer, each and everytime the arrow is shot, the effort has to be 100%.  A solid hit anywhere but the sand usually destroys an aluminum arrow and your spirits.  If your shooting isn't good one day, quit and try again later.  It is a very mental game, but that's what makes archery magical! 

My last target butt building effort resulted in a two sided pyramid.  The base is 5 foot long, about 3 foot high.  The target face is only 24 inches wide, but I find this to be plenty.  It took 750 lbs of sand ($45 worth) to fill.  With this design, I can shoot from opposite directions.  In my side yard, I have positioned the trap at the base of a steep incline, allowing both flat terrain and downhill shots.  A lightweight framework sheeted with corrugated plastic roofing panels keeps the weather out and allows the sun to warm and dry the sand during the day.  When covered, the sand trap looks like a cold frame.

If you are tired of damaged fletching, bent arrows, lost broadheads and inserts, messy rotting straw bales or the annual expense for big blocks of unsightly foam rubber then the sand trap offers a user friendly alternative.  Archery is supposed to be free from frustration.  Any improvement to level of comfort adds not only to the enjoyment of it all, but also will improve your shooting.

Good luck and good shooting.