New 155gr 6.5mm Berger on the horizon?

[fredo]

Define "season"

If you're inferring about firing new brass in the chamber before actual testing, then...yes.
Easy to do when you're FF-ing for a wildcat, or any necked up/down cartridge. Makes good sense to let the brass form to that particular chamber, then minimally resize them before stomping on the pedal during pressure testing...

 

[Grimstod]

Define "season"

If you're inferring about firing new brass in the chamber before actual testing, then...yes.
Easy to do when you're FF-ing for a wildcat, or any necked up/down cartridge. Makes good sense to let the brass form to that particular chamber, then minimally resize them before stomping on the pedal during pressure testing...

I may be using the wrong term "Season". To me its brass that has had a mid range load run through it for at least three reloads. At that point the heads of the brass get harder and I have seen, for example, my 6.5x47 was able to then handle 1.5gr of additional powder compared to when it was just fire formed once. The BRX could take another 1gr after four firings and PPC can usually handle between 1-2gr more. This has nothing to do with size of the brass, just the heads of the brass getting harder. Fire formed brass is what I would call that term and is something else to me altogether.

 

[fredo]

Sorta, pretty much what I described above.
The extra 'handling ability' could be attributed to 'hardening' of the brass from successive firings. But beyond that, a mild initial load allows the brass to 'stretch' to fit that chamber without over-pressuring/over-stressing the web area...

If ya go too hot on any initial firing of new brass, you're most assuredly negatively affecting future case life. Not to mention, blowing out the primer pockets prematurely. Both of those instances would not help in how that case handles pressure on subsequent firings...

My point above was about assuming the use of the same powder charge (42gr H4350) for a ~10-15% heavier bullet. A cursory glance to compare bearing surfaces doesn't account for that extra mass.
Physics tells us that the same energy (work) against a larger mass (action) has an equal & opposite (reaction). That 'reaction' will manifest in increased case pressure...

Just sayin', ya can't assume the charge weight for a 130-140gr bullet will be safe with a 155, based on bearing surface, alone.

 

[284winner]

QL shows .264, 155, Sierra HPBT LR MatchK 9570, apparently Sierra does not make it anymore.
http://forum.accurateshooter.com/threads/sectional-density-and-long-range-bullets.3738166/
see second post down

Yep I'm aware of that bullet they made some years ago. Just haven't seen it in their lineup in some time. If I'm not mistaken that 155 SMK was inferior in ballistic coefficient to the 142 SMK. Could be wrong it's been a while since I've used them.

 

[JBT47]

Yep I'm aware of that bullet they made some years ago. Just haven't seen it in their lineup in some time. If I'm not mistaken that 155 SMK was inferior in ballistic coefficient to the 142 SMK. Could be wrong it's been a while since I've used them.

I believe it was inferior to the 142

 

[284winner]

I believe it was inferior to the 142

Yep was thinking that too. Probably why it was discontinued as a match bullet. No real advantage.

 

[ImBIllT]

I wonder if they would be stabile in an 8.5" twist at 3500' on a warm day...

 

[Grimstod]

I wonder if they would be stabile in an 8.5" twist at 3500' on a warm day...

Your SG would be 1.48 so that is stable but you will loose a little BC.

 

[Grimstod]

More news on these bullets soon from a trusted source.

 

[Grimstod]

Looks like the 2760fps accuracy node for 6.5x47 and 6.5CM is pretty solid. Consistent .3moa or better and this is with a short 24in barrel. OAL is quite long though and Creedmoors will have a hard time feeding unless you have a magazine that is over 3in. The author had to single feed his creedmoor. The 6.5x47 is ok though and feeds fine thanks to its slightly shorter case. ES has been in the single digits and one report with the above loads was 3.6 for several groups. .020 off the lands seams to work best in several test cases. Loads are worked up using H4350. No hard bolt lift or ejector swipes.

 

[Grimstod]

 

[johnnyi]

View attachment 1033661

Can you turn to page 12 for more details?

 

[Grimstod]

Wish i could. This i found on FB. Someone at shot show posted it.

 

[Ringostar]

Can you turn to page 12 for more details?

I know someone that was included in the testing. He sent me a pic of a 10 shot 1000yd group. All 10 in a group smaller than the 5" X ring.

 

[284winner]

When i said game changer i sorta meant for the 6.5-284. Years ago it was the caliber of choice for 1000y but now almost everyone has switched to the 284 because of some really good high bc bullets. With this high BC 6.5mm bullet would some swithc back?

Absolutely.

 

[284winner]

Hey guys I didn't see anyone address the fact that hornady already has the 147eld G7.351 G1 .697 form factor .858!!!! It will need a G7 BC of around .370 to equal the 147 eld in form factor. This Berger bullet is going to have to be pretty impressive to trump these figures!!!!!

It will. Plus in bergers historic track record, accuracy will be very good I'm sure. Just have to dish put a few more pennie's per bullet as is also in bergers track record...expensive bullets.

 

[sdean]

Absolutely.

Game changer on paper. I quit the 6.5-284 over barrel life in a fclass gun. Is anybody really winning with heavy for caliber bullets? I know the barrel makers must love them. Every time one comes out you need a new barrel.

 

[284winner]

Game changer on paper. I quit the 6.5-284 over barrel life in a fclass gun. Is anybody really winning with heavy for caliber bullets? I know the barrel makers must love them. Every time one comes out you need a new barrel.

Hopefully not in this case. It's a hunting gun and hoping the 8 will stabilize them at 3000+ fps

 

[Steveb]

I have found that the 152 Matrix stabilizes in a 1 in 8 at 2720 fps. A 1 in 7.5 maybe better and when my order gets in then I will find that out but the 1 in 8 does well.

 

[KMG]

I have found that the 152 Matrix stabilizes in a 1 in 8 at 2720 fps. A 1 in 7.5 maybe better and when my order gets in then I will find that out but the 1 in 8 does well.

The 160 Matrix with a 1-8 in my 6.5ss were stable. I ran them up to just shy of 3200' too.