6XC bullet choice - 105gr berger hybrid or 107gr Sierra MK

[gunmutt]

For all you 6XC shooters out there what is the benefit and drawback in choosing one over the other?
I have a 7.5 twist criterion barrel and several pounds of H4350 stocked up.

 

[zipollini]

If you run the ballistics thru JBM ballistics calculator you will find that the Berger hybrids have a slightly higher G1 BC.

At 1000 yds @ 70 deg., sea level, 3150 fps

Berger
23.2 MOA drop or 242.5 inch drop

Sierra
24.0 MOA drop or 251 inches drop

I've also thrown in the numbers for the soon to arrive DTAC 115 rbt with a projected G1 BC of .620. Most folks including myself shoot these at around 3000 fps

At 1000 yds @ 70 deg.. sea level , 3000 fps
24.3 MOA drop or 254 inches drop

At 1000 yds @ 70 deg, sea level, 3050 fps
23.3 MOA drop or 244 inches drop

 

[FatBoy]

Run the wind numbers too. Drop is way easier to correct for than wind.

That said, I have shot both in my 6BRs and I don't see any difference in scores between the two bullets out to 1k. The new~ish pointed 107s are an excellent bullet and it's what we shoot. Nothing against the hybrid, but for the money they 107s do it for me.

 

[6xcshooter]

Those bullets are so close in ballistics try both. As always you must try them in YOUR rifle to see which one shoots the best . All the calculating and speculating don't mean squat till you see how they shoot from your barrel. That's the only way i do my load choices.

 

[tbeasley]

Throw the BC numbers out the window, if your shooting BR than you already know the distance. Concentrate on which bullet hits the mark shot after shot. You need to test the bullets in a controlled environment and do several 10 to 15 shot groups at 3-400yds. If you can stretch it out further great. This will tell you which bullet works best in your barrel at the desired speed your wanting to achieve.
I shoot 6xc exclusively and shoot it at dasher speeds. (3015fps) and it absolutely hammers.
Pay close attention to vertical. 107 SMK'S love jam.
Every gun is its own science experiment

 

[dbduff]

Throw the BC numbers out the window, if your shooting BR than you already know the distance. Concentrate on which bullet hits the mark shot after shot. You need to test the bullets in a controlled environment and do several 10 to 15 shot groups at 3-400yds. If you can stretch it out further great. This will tell you which bullet works best in your barrel at the desired speed your wanting to achieve.
I shoot 6xc exclusively and shoot it at dasher speeds. (3015fps) and it absolutely hammers.
Pay close attention to vertical. 107 SMK'S love jam.
Every gun is its own science experiment

Shot a 20 round match today with 107's and H4350 just touching. How much jam are you talking about? I'm just starting to work with this load, but seems to shoot as well as Berger 108's .005 off jam.
D

 

[tbeasley]

Shot a 20 round match today with 107's and H4350 just touching. How much jam are you talking about? I'm just starting to work with this load, but seems to shoot as well as Berger 108's .005 off jam.
D

I've had great results with a +.009 after kiss.
I do measure and segregate bullets base to ogive. Seat bullets with in-line die I built myself. My 27" bbl with 37.8-38.2gr of H4350 gives me a great accuracy window.
Berger 108's are easy to tune also and shoot real well.

 

[dbduff]

I've had great results with a +.009 after kiss.
I do measure and segregate bullets base to ogive. Seat bullets with in-line die I built myself. My 27" bbl with 37.8-38.2gr of H4350 gives me a great accuracy window.
Berger 108's are easy to tune also and shoot real well.

Thanks for prompt response, was shooting 37.9 and showed promise. Will try your jam, haven't started base to ogive measurements yet. Thanks again,
D

 

[majohnson]

While I have no experience with the 107, I have shot almost 300 rounds of 105 VLD with great results. The 107 jacket material is harder them what Berger uses. Not to charge the post, but anyone found the VLD to be speed sensitive?

 

[Terry Altom]

I've had great results with a +.009 after kiss.
I do measure and segregate bullets base to ogive. Seat bullets with in-line die I built myself. My 27" bbl with 37.8-38.2gr of H4350 gives me a great accuracy window.
Berger 108's are easy to tune also and shoot real well.

One quick question for you. How much neck tension are you using?

 

[tbeasley]

One quick question for you. How much neck tension are you using?

The math doesn't work, but I'm using a .265 redding nitrided bushing, and my loaded rounds measure .2635-.264 (there was talk sometime back that the bushing measurements differ slightly from bushing to bushing than what's stamped)
I turned all my brass and the .265 bushing puts tension on all the brass. I realize it shouldn't. But it does and does it well. I do use the mandrel and remember the mandrel is the last thing that passes thru your case neck and gives you your ID and OD measurements. So your mandrel OD is just as important. I realize they are pretty standard. But I think Forrester has different sized buttons to choose from.
So my neck tension isn't very much at all. Sorry for vague answer.

 

[ASbobcat]

For all you 6XC shooters out there what is the benefit and drawback in choosing one over the other?
I have a 7.5 twist criterion barrel and several pounds of H4350 stocked up.

I found that for me the 107's liked to be seated "on the lands", which can be a problem. First, because the lands move as the throat wears and secondly because I had to be very precise when seating the bullets. I have found most VLD's (6 and 6.5mm) like to jump about .015 +/-.005, so seating is not as critical. Too bad you have so much H4350. RL17 will give you 100-150fps more velocity with the same accuracy. And don't believe those who say RL17 is temperature sensitive, at least not in my experience. I'm getting 2950fps in my 6BR with 105's in a 30in Savage factory barrel.

 

[boltfluter]

What testing have you done to test temperature sensitivity of RL17.
Considering doing an XC and shooting RL17. Thanks for any info and tips.

Paul

www.boltfluting.com

 

[dbduff]

I've had great results with a +.009 after kiss.
I do measure and segregate bullets base to ogive. Seat bullets with in-line die I built myself. My 27" bbl with 37.8-38.2gr of H4350 gives me a great accuracy window.
Berger 108's are easy to tune also and shoot real well.[/QUOTE

Your info has been real helpful to me regarding 107's. Have found Wolf primers seem to have edge over Br2. What are your thoughts regarding primers?
D

 

[ASbobcat]

What testing have you done to test temperature sensitivity of RL17.
Considering doing an XC and shooting RL17. Thanks for any info and tips.

Paul

www.boltfluting.com

I shoot in North Texas where we have a wide variation in temps. I have chrono'd and check accuracy from 40deg to 100deg and have not found any appreciable difference. Another advantage is that RL17 meters well.

 

[boltfluter]

I shoot in North Texas where we have a wide variation in temps. I have chrono'd and check accuracy from 40deg to 100deg and have not found any appreciable difference. Another advantage is that RL17 meters well.

Bobcat,

Thanks for the info. Sounds like RL17 is a perfect match for the
6XC. Seriously considering building one.

Thanks, Paul

www.boltfluting.com

 

[ASbobcat]

Paul,

I originally bought RL17 for my 6.5x47Lapua and assumed, as did many others, that it would be too slow for the 6BR. Turns out that it is only slightly slower than RL15 and is perfect in the 6BR or Dasher. My load in the 6.5 is only about 90% capacity, but that gives me 2800fps with 140gr Bergers (26in bbl). That seems to be as good as anyone is getting with good brass life. RL17 should work well in the 6XC. I'm hoping Alliant will switch more of their line to the new Swiss Nitrochemie formula. If they do, RL19 might be a better match to the XC/47L case.

Bob

 

[dcali]

The 107's over H4350 shot so well in my rifle that it seemed stupid to spend the extra cash on the Bergers, although I hear great things about those as well.

 

[tbeasley]

Your info has been real helpful to me regarding 107's. Have found Wolf primers seem to have edge over Br2. What are your thoughts regarding primers?
D
Funny you ask, I start most load development with CCI 200's. Once I get powder and bullets and all the other factors ironed out. I usually switch over to Federal Gold Medal primers.
Primers are last on my list to switch and tune load with. IMO primers don't present huge accuracy swings. But they are good for the FINE tuning.

 

[tbeasley]

They just work