Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Since there has been no shortage of questions on this wildcat, here is the background.
Why? To build an economical cartridge to launch very high BC match bullets at extreme distances for target and hunting. A "BMG" without the hassles.
This cartridge is based on an improved and modified 300RUM with a long throat. The goal is to launch the 300gr Sierra MK at over 3000fps in long barrels.
My rifle has a 36" barrel, 34.5" rifled with an integral muzzle port/brake.
This family of cartridges is lead by the 338-416 Rigby improved and 338-378 Weatherby (reg. and improved verions). These cannons can easily push a 300grMK at 3100 to 3300fps in long barrels. Serious horsepower but brass is expensive, not always easy to find and life short.
My 338 Mystic and the 338 Tomahawk came about when the 300RUM came out. There was now a readily available and inexpensive source of large capacity brass. Case capacity will never be the same but gets you close. Long throating allows for max amount of case capacity. These rifles are all single feed except if you put them into BMG sized action. OAL exceeds 3.3".
In long barrels, 3000 to 3200fps have been reached with great accuracy. This can only be accomplished with very slow powders. The most commonly used are surplus pulldown from BMG and Vulcan ammo. Yep, burn rates just a bit faster then wet sawdust.
This allows one to approach 100% load density. Powder charges for my RUM based wildcats exceed 100gr. Some rifles have run up as far as 110gr. That's toasty.
By comparision, the Rigby and Wby monsters get into the 115 to 125gr range. The Lapua in the low 90's. 340Wby in the 80's.
For those interested in the biggest baddest LR cannon that you don't need boutique or single component source, the 338-300RUM based wildcats are it for now. Best part is that any quality magnum action can house this case. So you don't need to splurge for expensive actions unless you want to build BR quality rigs.
Factory and large surplus actions (Enfield P14's) with a quality barrel can easily produce 1/2MOA or better accuracy. Barrel blocks are common fare to help balance/hold barrels that weight well over 10lbs and 36".
These type of rifles are definitely not for walking about hunting. Shot from portable benches and pedestal rests, these are designed to make extreme range hits possible. Mine will exceed 35lbs when ballasted.
Are they necessary for extreme range plinking? Not anymore. new bullets in 7mm and 6.5mm offer very similar ballistics for way less recoil and costs.
However, if you want horsepower way out there, bore size and bullet weight will always win.
Jerry
Why? To build an economical cartridge to launch very high BC match bullets at extreme distances for target and hunting. A "BMG" without the hassles.
This cartridge is based on an improved and modified 300RUM with a long throat. The goal is to launch the 300gr Sierra MK at over 3000fps in long barrels.
My rifle has a 36" barrel, 34.5" rifled with an integral muzzle port/brake.
This family of cartridges is lead by the 338-416 Rigby improved and 338-378 Weatherby (reg. and improved verions). These cannons can easily push a 300grMK at 3100 to 3300fps in long barrels. Serious horsepower but brass is expensive, not always easy to find and life short.
My 338 Mystic and the 338 Tomahawk came about when the 300RUM came out. There was now a readily available and inexpensive source of large capacity brass. Case capacity will never be the same but gets you close. Long throating allows for max amount of case capacity. These rifles are all single feed except if you put them into BMG sized action. OAL exceeds 3.3".
In long barrels, 3000 to 3200fps have been reached with great accuracy. This can only be accomplished with very slow powders. The most commonly used are surplus pulldown from BMG and Vulcan ammo. Yep, burn rates just a bit faster then wet sawdust.
This allows one to approach 100% load density. Powder charges for my RUM based wildcats exceed 100gr. Some rifles have run up as far as 110gr. That's toasty.
By comparision, the Rigby and Wby monsters get into the 115 to 125gr range. The Lapua in the low 90's. 340Wby in the 80's.
For those interested in the biggest baddest LR cannon that you don't need boutique or single component source, the 338-300RUM based wildcats are it for now. Best part is that any quality magnum action can house this case. So you don't need to splurge for expensive actions unless you want to build BR quality rigs.
Factory and large surplus actions (Enfield P14's) with a quality barrel can easily produce 1/2MOA or better accuracy. Barrel blocks are common fare to help balance/hold barrels that weight well over 10lbs and 36".
These type of rifles are definitely not for walking about hunting. Shot from portable benches and pedestal rests, these are designed to make extreme range hits possible. Mine will exceed 35lbs when ballasted.
Are they necessary for extreme range plinking? Not anymore. new bullets in 7mm and 6.5mm offer very similar ballistics for way less recoil and costs.
However, if you want horsepower way out there, bore size and bullet weight will always win.
Jerry
Last edited:
