Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
I have seen alot of the same question being asked from those wanting to get started in LR shooting, F class mostly. Thought I would put down some options that is working in most LR disciplines. Since bullets are what is driving advancements, we have to start there.
With F class being the fastest growing form of LR shooting, I will focus on this. Most other LR shooting like BR will also use the same/similar choices depending on overall weight allowed.
At this time, bullets are coming to the 'end' of useable weights. Apparently, when bullets need a twist faster then 1 in 7, you hit a wall. If someone figures out how to build a bullet differently, we may be able to make bullets more streamlined.
The main choices are 6mm, 6.5mm, 7mm. The 30 and 338 are very specialized cals used only in unlimited weight or muzzle braked classes. Recoil is simply too high in 'light' weight classes.
The 308 and 223 are usually limited by the rules of their respective sports. These would certainly NOT be used when other cals are allowed. Shooting either in F-Open would be a severe handicapp if shooting beyond 300m.
6mm:
Bullets: 105/107gr for moderate ranges like 600m or out to 1k in calmer conditions. The 115gr is better suited to 1k type events.
Cartridges: 6BR is the smallest and does an excellent job with the 105/107 family of bullets. The larger XC, Lapua, and now 243 and variants work much better with the 115gr.
Velocities: Ideally, all will approach 3000fps muzzle velocity. There are some pushing the 115gr to 3200fps and this improves wind drift substantially.
Barrel length: 30" is a nice compromise but size will be determined by class overall weight.
Wind rating: Of the three cals, the 6mm has the lowest BC bullets so for a similar velocity, drifts more. Running elevated velocity helps but then there are issues with the bullets themselves.
6.5mm:
Bullets: 139gr/142gr bullets are the best for out to 1k shooting. For 600m and in, there is strong interest in 123gr class bullets. All can easily be pushed to 3000fps with the lighter ones approaching 3300fps. The common twist of 8/8.5 indicates that there is room to build longer bullets. So far, no one has come up with a higher BC design. Math would suggest that a 150ish VLD bullet with BC over 0.65 is possible.
Cartridge: Most common is the 6.5-284. Works but I consider the case volume a bit big. Most rifles push the 140 class of bullets around 2900 to 3000fps. The 284 case is larger then it needs to be. However, if someone wants to go 3100+fps, then a great one. If there is a 150ish VLD bullet, then the 284 will become ideal.
260, 260AI/6.5 Mystic, 6.5X55/AI I consider to be better choices. The larger cases will match the common 6.5-284 velocity, use 10% to 15% less powder too.
Velcocity: 139 to 142gr bullets don't seem to like going much over 3000fps. Most are running 2900 to 2950fps with some even going slower. The lighter bullets don't seem to mind going over 3000fps.
Barrel length: 30" is a great length for this cal.
Wind drift: Pretty much the ideal combo of wind drift vs recoil. Wind drift is measurably less then the 6mm at reg. speeds.
For a non cal specific shooting class, this is the cal to beat!
7mm:
Bullets: You get very high BC bullets in this cal. The 162gr Amax lists at 0.625 and certainly flies like that. The Bergers push the limits with their 180gr at 0.675 or so. Very few bullets can match this type of BC. In general, the Sierra MK are low BC for their bullet weight. Not alot of choices yet but that is changing quickly.
Cartridge: There are some playing with the 284 at very high pressures. Sometimes they work, sometimes, not so good. Larger cases like the 280AI/7 Mystic, RSAUM and WSM are ideal for the 162 to 180gr class of bullets.
Velocity: Most will try for at least 2900fps. With the large magnum cases, 3000fps with the 180gr Bergers is possible. These bullets do not like going faster and there is definitely no need to do so.
Barrel length: 30" for sure.
Wind drift: By far, this offers the lowest wind drift of the three. In fact, the wind drift of the 180gr Berger equals or better some of the really heavy 30 and 338 offerings. There have been reports of bullet blow up but QC seems to be improving.
Recoil: There is always a trade off and the recoil of this cal is it. With the 162 to 180gr bullets, recoil is harsh even in a 10KG rifle. A few shots in a hunting application is no problem but trying to shoot 60rds in a day ACCURATELY will be taxing to many.
Cost: Bigger is definitely more expensive per bang. Also, component availability in Canada can be problematic.
This is a cal that will see the most development over the next 6 months. It offers real world ballistic advantages but I don't see this taking a huge bite from the other cals as shooter fatigue is a real problem and must be considered.
So will barrel heat and wear.
The 7mm will really start to show its importance in heavy gun 1000yd/m class or sports that allow muzzle brakes. For F class, the interest is growing at events out to 1000yds/m where high winds are expected. Some believe the reduced wind drift is worth the beating.
For LR shooting, the number of possible choices is shrinking as we fully development how bullets work at distance. There are really two bullet weight class for each cal and the only real choice is the combustion chamber chosen to launch them.
Unless new bullets come out soon, by the end of 2007, there will be two best choices for 600m and shorter, and three choices for beyond.
As far as accuracy, they are all equally accurate. The trade off will be ballistics (wind drift) vs recoil (weight of class/muzzle brakes) vs heat/wear/costs.
Hope this helps...
Jerry
With F class being the fastest growing form of LR shooting, I will focus on this. Most other LR shooting like BR will also use the same/similar choices depending on overall weight allowed.
At this time, bullets are coming to the 'end' of useable weights. Apparently, when bullets need a twist faster then 1 in 7, you hit a wall. If someone figures out how to build a bullet differently, we may be able to make bullets more streamlined.
The main choices are 6mm, 6.5mm, 7mm. The 30 and 338 are very specialized cals used only in unlimited weight or muzzle braked classes. Recoil is simply too high in 'light' weight classes.
The 308 and 223 are usually limited by the rules of their respective sports. These would certainly NOT be used when other cals are allowed. Shooting either in F-Open would be a severe handicapp if shooting beyond 300m.
6mm:
Bullets: 105/107gr for moderate ranges like 600m or out to 1k in calmer conditions. The 115gr is better suited to 1k type events.
Cartridges: 6BR is the smallest and does an excellent job with the 105/107 family of bullets. The larger XC, Lapua, and now 243 and variants work much better with the 115gr.
Velocities: Ideally, all will approach 3000fps muzzle velocity. There are some pushing the 115gr to 3200fps and this improves wind drift substantially.
Barrel length: 30" is a nice compromise but size will be determined by class overall weight.
Wind rating: Of the three cals, the 6mm has the lowest BC bullets so for a similar velocity, drifts more. Running elevated velocity helps but then there are issues with the bullets themselves.
6.5mm:
Bullets: 139gr/142gr bullets are the best for out to 1k shooting. For 600m and in, there is strong interest in 123gr class bullets. All can easily be pushed to 3000fps with the lighter ones approaching 3300fps. The common twist of 8/8.5 indicates that there is room to build longer bullets. So far, no one has come up with a higher BC design. Math would suggest that a 150ish VLD bullet with BC over 0.65 is possible.
Cartridge: Most common is the 6.5-284. Works but I consider the case volume a bit big. Most rifles push the 140 class of bullets around 2900 to 3000fps. The 284 case is larger then it needs to be. However, if someone wants to go 3100+fps, then a great one. If there is a 150ish VLD bullet, then the 284 will become ideal.
260, 260AI/6.5 Mystic, 6.5X55/AI I consider to be better choices. The larger cases will match the common 6.5-284 velocity, use 10% to 15% less powder too.
Velcocity: 139 to 142gr bullets don't seem to like going much over 3000fps. Most are running 2900 to 2950fps with some even going slower. The lighter bullets don't seem to mind going over 3000fps.
Barrel length: 30" is a great length for this cal.
Wind drift: Pretty much the ideal combo of wind drift vs recoil. Wind drift is measurably less then the 6mm at reg. speeds.
For a non cal specific shooting class, this is the cal to beat!
7mm:
Bullets: You get very high BC bullets in this cal. The 162gr Amax lists at 0.625 and certainly flies like that. The Bergers push the limits with their 180gr at 0.675 or so. Very few bullets can match this type of BC. In general, the Sierra MK are low BC for their bullet weight. Not alot of choices yet but that is changing quickly.
Cartridge: There are some playing with the 284 at very high pressures. Sometimes they work, sometimes, not so good. Larger cases like the 280AI/7 Mystic, RSAUM and WSM are ideal for the 162 to 180gr class of bullets.
Velocity: Most will try for at least 2900fps. With the large magnum cases, 3000fps with the 180gr Bergers is possible. These bullets do not like going faster and there is definitely no need to do so.
Barrel length: 30" for sure.
Wind drift: By far, this offers the lowest wind drift of the three. In fact, the wind drift of the 180gr Berger equals or better some of the really heavy 30 and 338 offerings. There have been reports of bullet blow up but QC seems to be improving.
Recoil: There is always a trade off and the recoil of this cal is it. With the 162 to 180gr bullets, recoil is harsh even in a 10KG rifle. A few shots in a hunting application is no problem but trying to shoot 60rds in a day ACCURATELY will be taxing to many.
Cost: Bigger is definitely more expensive per bang. Also, component availability in Canada can be problematic.
This is a cal that will see the most development over the next 6 months. It offers real world ballistic advantages but I don't see this taking a huge bite from the other cals as shooter fatigue is a real problem and must be considered.
So will barrel heat and wear.
The 7mm will really start to show its importance in heavy gun 1000yd/m class or sports that allow muzzle brakes. For F class, the interest is growing at events out to 1000yds/m where high winds are expected. Some believe the reduced wind drift is worth the beating.
For LR shooting, the number of possible choices is shrinking as we fully development how bullets work at distance. There are really two bullet weight class for each cal and the only real choice is the combustion chamber chosen to launch them.
Unless new bullets come out soon, by the end of 2007, there will be two best choices for 600m and shorter, and three choices for beyond.
As far as accuracy, they are all equally accurate. The trade off will be ballistics (wind drift) vs recoil (weight of class/muzzle brakes) vs heat/wear/costs.
Hope this helps...
Jerry
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