215 grain hybrid loads for 308???

[rap36case]

I am intrigued by the 215grn Berger hybrid for 308win. I know Bryan Litz used it to win F/TR with 30" 1 to 9 twist. I have been experimenting with my Shilen built 308 with 24" 1 to 10 twist. I have found a node (sweet spot) at 42.1grains Varget, Lapua palma small primer brass, BR4 primer, 215gr HB. I get 0.2" verticle and .4 horizontal at 100 yards. At 42.4 the group goes to 1". The muzzle velocity measured with MagnetoSpeed is 2550fps, and estimated terminal velocity at 1000y of 1489fps (elevation 1000ft, 59F). This seems to be well above transonic at 1000 yards.

I realize the bullet is seated well into the case and the COAL is still 3.005". It is a compressed load under these conditions, just starting to crunch the Varget. I do not know what COAL Dr. Litz used, or the throating (freebore) used to accommodate this bullet. Still, it seems to work with single feed and 0.015" jump in my rifle. I may replace the barrel later with a Krieger in 1 to 9 twist, I just don't know if I will go to 30".

So, why do people tell me this load can not take advantage of the G7 BC for this bullet?

 

[Jay Christopherson]

I believe that with a 1:10 twist barrel, at that velocity, that you have a slightly less optimal stabilization factor (Sg) which means that the realized BC is going to be a little less than is possible for that bullet. You can review the info here:

http://www.bergerbullets.com/twist-rate-calculator/

looks like roughly 3% less than is possible with a faster twist barrel. That doesn't mean that your accuracy won't be good though...

 

[dcali]

Keep in mind that this is a very rough measure.

 

[XTR]

Depends on who the people are who are telling you it won't work and whether or not they actually have any clues.

Shoot it and see if it works for you. (and watch your primer pockets)

However, keep in mind that if you are not reading wind well enough to stay in the 10 ring with a 185, you are not going to stay in the 10 ring with a 215 either. Except at 6800 feet ASL at Raton, neither will hold the 10 ring if you miss a 1MPH pickup or letoff. The advantages of the higher BCs of the 200s or the 215s plays out at the end of the weekend. You will probably agg one to three points higher over 5 matches.

If you aren't competing for the top of the leader board they really only get you more recoil, make it harder to diagnose position errors (though they will show them in spades), less $$ to buy other stuff since they cost more than other bullets and you are probably beating the crap out of your brass.

 

[Ned Ludd]

For 30" barrels, 2550 fps is very close to what others have identified as a known accuracy node. To get that same velocity from a 24" barrel, combined with a sub-optimal freebore length suggests you're running extremely high pressure. Using your specific values (barrel = 24", COAL = 3.005" 42.1 gr Varget, 2550 fps), Quickload predicts your pressure to be in excess of 76K psi, which would be a stupid-hot load. The reason for not using 215s in a 24" barreled rifle has little to do with the slight loss of BC from a 10-twist barrel, it has much more to do with the low velocities that most sane people would obtain by loading to reasonable pressure. In a 24" barrel, that would mean somewhere in the low 2400 fps range, not 2550.

Another reason the 215s haven't quite caught on the way their BC suggests they should or could is because some people simply can't effectively control the recoil of a 215 at about 2550 fps in an 18 lb F-TR rifle. Recoil management with the heavies requires much more from the shooter than when using lighter weight (< 200 gr) bullets.

 

[rap36case]

I believe that with a 1:10 twist barrel, at that velocity, that you have a slightly less optimal stabilization factor (Sg) which means that the realized BC is going to be a little less than is possible for that bullet. You can review the info here:

http://www.bergerbullets.com/twist-rate-calculator/

looks like roughly 3% less than is possible with a faster twist barrel. That doesn't mean that your accuracy won't be good though...

Thank you for the link and estimate of improvement! I will use 1 to 9 twist, when I need to replace the barrel.

 

[rap36case]

For 30" barrels, 2550 fps is very close to what others have identified as a known accuracy node. To get that same velocity from a 24" barrel, combined with a sub-optimal freebore length suggests you're running extremely high pressure. Using your specific values (barrel = 24", COAL = 3.005" 42.1 gr Varget, 2550 fps), Quickload predicts your pressure to be in excess of 76K psi, which would be a stupid-hot load. The reason for not using 215s in a 24" barreled rifle has little to do with the slight loss of BC from a 10-twist barrel, it has much more to do with the low velocities that most sane people would obtain by loading to reasonable pressure. In a 24" barrel, that would mean somewhere in the low 2400 fps range, not 2550.

Another reason the 215s haven't quite caught on the way their BC suggests they should or could is because some people simply can't effectively control the recoil of a 215 at about 2550 fps in an 18 lb F-TR rifle. Recoil management with the heavies requires much more from the shooter than when using lighter weight (< 200 gr) bullets.

This is wise advice. I have noticed pressure signs when using BR2 in large primer brass. Not something you want to do all the time, but it seems to have worked for one F/TR winner with 30" barrel. I am guessing 20fps per inch advantage?
Recoil control with special bipod and other techniques may be how it's done. I have yet to shoot at 1000yards.

 

[XTR]

If you have yet to shoot at 1000 yards you are chasing up the wrong trail trying to learn to shoot 215s from the start, but you aren't going to believe that yet.

Look at what the US team shoots (hint:200s). In 2013 they shot the 185s (and won the world championship). In F-TR it is not the arrow.

Where 200s and 215s make the biggest difference is when you are shooting at 1000 yards. When the 200hybrid needs 3.4 MOA in a given wind condition and the 215 only needs 3.1 then the shooter using the 215 has a 9% smaller range in which to make corrections when there is a change, if you use the 200-20X and make that calculation it's a 6% range. That adds up to a point here and a point there. At the top of the leader board in a 5 day match that is big, but for an average shooter it's not going to pay off.

As I recall the rig Bryan ran at Phoenix had a carbon fiber stock with a recoil absorber in the buttplate.

and

If you normally don't shoot beyond 600 you are really wasting your time.

If you are getting pressure signs on Palma Brass you've broken it. It probably won't hold a primer for another shot. Been there done that 4 yrs ago, and I won't publicly admit how fast I had 215s running, but Lapua Palma wouldn't hold a primer after one shot.

You are going to do what ever you want to do, and free advice is probably worth what you pay for it, but you should look carefully before you leap.

 

[rap36case]

I am going to back down to 2450fps with the BR4 primers. I have seen no pressure signs with the hotter load, but I do not need to push my luck. I am an 'experimentalist', and believe numbers more than theoretical calculations. I have seen critical review of the Quickloads, and will error on the side of caution.

No, not seeing pressure signs with the Palma brass. The primers are not 'top hat' or flat and the pockets are still tight. However, the stiffer base may be more prone to catastrophic failure when limits are exceeded.

Funny, tactical enthusiasts encourage me to go hotter. They offer no data other than gut feelings. They often shoot magnums, 338 etc. I am not a recoil junky. I like shooting distance, but I am not willing to take risks.

 

[Ned Ludd]

This is wise advice. I have noticed pressure signs when using BR2 in large primer brass. Not something you want to do all the time, but it seems to have worked for one F/TR winner with 30" barrel. I am guessing 20fps per inch advantage?
Recoil control with special bipod and other techniques may be how it's done. I have yet to shoot at 1000yards.

It's important to note that the Quickload values are only predictions. However, in my hands they are typically pretty solid for relative comparisons, even if the absolute values may not be spot on. I have a good input for Palma brass case volume, and when combined with your velocity and case measurements, it spells very high pressure, even for Palma brass. When it comes to pressure, barrel length is not solely enough to get a good estimate as based on its effect on velocity. As barrel length goes up, generally so does velocity for a given charge weight. But you also have to take into account the volume of the pressure cell (total case volume combined with seating depth, or effectively, COAL). A rifle chambered with a very long throat that is optimized for the 215s will have greater effective case volume, and therefore will be able to reach a given velocity at lower pressure.

The setup and load you described not only suffers from a shorter than typical barrel, it also has a short freebore so that your effective case volume is low relative to a rifle with a longer freebore. Based on the QL estimate, you're running the 215s at about 100 fps or more faster than would be expected from a load that was approximately at SAAMI MAX pressure of 62K psi. Palma brass can certainly take higher pressure for a longer period of time than standard large rifle primer .308 brass. However, I'd say it's not unreasonable to predict your load is well above that. You might get away with it for a while, but you should consider the long strings of fire we shoot in F-Class and what the increased barrel/action heating will do to that load, especially on a hot summer day. My suggestion would be that if you want to push 215s in the 2550 fps range, you really want a barrel length and freebore length that can give that velocity at reasonable operating pressures. At that point, you can decide whether you can manage the recoil or not. But there's no reason to have to be worrying about both recoil and high pressure at the same time.

 

[Capt. Oblivious]

I shoot them out of my 1/10 twist 06 a tad under 2600fps and its the most consistantly accurate/devastating bullet I have ever used in any rifle. I shoot the 200gr Hybrids in my 300WM and the 215gr really is all that imo, only problem as stated is the added recoil but when you see that 215gr bullet driving into a steel plate its all worth it.

 

[Berger.Fan222]

The 208 ELD is well stabilized and will achieve its full advertised BC in a 1 in 10" twist from a .308. The heavier Berger bullets will not (near sea level). They require a 1 in 9" twist.

 

[DukeDuke]

I've had good results with the 215s in a 1 in 11" at sea level.

 

[Berger.Fan222]

I've had good results with the 215s in a 1 in 11" at sea level.

So have we, as long as you define "good results" in terms of accuracy and low ES without putting a radar on the bullet and measuring BCs. When we measure BCs, we see that the 208 ELD is very close to Hornady's number, but that the heavier Berger bullets have lost BC compared with what is measured in faster twist barrels. Berger/Litz are exactly right to recommend a faster twist for their heavier .308 bullets.

 

[Greg Brooks]

For the 215gr Berger, I get 2520fps as a mean with single digit std. deviation from a 32" (10x) Bartlein using large rifle Lapua Brass and 42.02gr of Varget in a trued Remington Action - NOTE - this barrel has been throated very long..

After the remaining 750 Bergers are used up (from the 3,500 lot purchase) we will give Lapua's 220gr a try. After sorting 3.5k of each, the 215gr Berger deviation within the sample size for base to ogive and weight is statistically different than that of Lapua's 220gr.


Turd Fergusson

 

[rap36case]

I've had good results with the 215s in a 1 in 11" at sea level.

I just realized that I said the barrel length is 24". It is in reality 26" and I do beg your pardon. This only makes a slight difference in estimating pressures. Taking a closer look at the brass, I have some 'craters' on the primers. However, the primers were tight in the pockets. I use an LE Wilson small decapping rod for the small primers.

 

[rap36case]

I just shot reloads this weekend at 1000yards with the Shilen 26" 1to10. I chronographed the 42.1grains of Varget at 2532fps, with no pressure signs. The results were amazing for me, as I have not shot 1000yards before. I used Applied Ballistics to create my range card with 1000yards at 28.5MOA, with 300yard zero. I just ordered another 250 of the 215grain Hybrid. I will try out to 1350 at the range next.

 

[T-shooter]

I am intrigued by the 215grn Berger hybrid for 308win. I know Bryan Litz used it to win F/TR with 30" 1 to 9 twist. I have been experimenting with my Shilen built 308 with 24" 1 to 10 twist. I have found a node (sweet spot) at 42.1grains Varget, Lapua palma small primer brass, BR4 primer, 215gr HB. I get 0.2" verticle and .4 horizontal at 100 yards. At 42.4 the group goes to 1". The muzzle velocity measured with MagnetoSpeed is 2550fps, and estimated terminal velocity at 1000y of 1489fps (elevation 1000ft, 59F). This seems to be well above transonic at 1000 yards.

I realize the bullet is seated well into the case and the COAL is still 3.005". It is a compressed load under these conditions, just starting to crunch the Varget. I do not know what COAL Dr. Litz used, or the throating (freebore) used to accommodate this bullet. Still, it seems to work with single feed and 0.015" jump in my rifle. I may replace the barrel later with a Krieger in 1 to 9 twist, I just don't know if I will go to 30".

So, why do people tell me this load can not take advantage of the G7 BC for this bullet?

My long distance load for my 22" Savage .308 is the 208 grain Hornady ELD with 41.5 grains of Varget (slightly compressed), Hornady match cases, and Federal match primers, set .025" off the lands for an average COL of 2.965". This load fires at an average of 2,430 fps. I get a slight ejector mark on maybe 1 out of 50. I loaded them hot but actually they seem to be reasonably accurate. I shot two 7 shot groups at 500 yards in 2-1/2 inches. Strange but this bullet seems to group almost as well at 500 yards as it does at 200 yards.

 

[rap36case]

My long distance load for my 22" Savage .308 is the 208 grain Hornady ELD with 41.5 grains of Varget (slightly compressed), Hornady match cases, and Federal match primers, set .025" off the lands for an average COL of 2.965". This load fires at an average of 2,430 fps. I get a slight ejector mark on maybe 1 out of 50. I loaded them hot but actually they seem to be reasonably accurate. I shot two 7 shot groups at 500 yards in 2-1/2 inches. Strange but this bullet seems to group almost as well at 500 yards as it does at 200 yards.

____

Thank you for sharing your reload. The long slim 'heavies' work well in the 308win. I have read that heavies have been shot at Camp Perry for decades due to the advantages in high winds. I read an article here about Dr. Bryan Litz winning F/TR at 1000y with the Berger 215 HB, that he designed. The 26" barrel seems to be just long enough that I do not see pressure signs, other than slight cratering in the small BR4 primers. I am 0.015" off the lands and the COAL is above magazine length. I know this would not do for some CMP and other contests where magazine is required.
I will shoot a series next 41.8 to 42.2 to verify the node or 'sweet' spot. I am guessing 42.0g will give me 2525fps muzzle velocity. If I zero at 300y, then the drop at 1000y is 28.5MOA according to Applied Ballistics calculator. These calculations have proven very accurate in the past.