Best cartridge for silhouette

[Trent]

Dan, I shot at River Bend last month in an F-class match. You aren't kidding, that is one nice range! I shot on their 600yd range and got to drive around the range a bit. They really have it set up nicely. Wish it wasn't a 3.5 hour drive though. Makes me have to get up and leave pretty early to make it to morning matches.

[DanDeMan]

Dan, I shot at River Bend last month in an F-class match. You aren't kidding, that is one nice range! I shot on their 600yd range and got to drive around the range a bit. They really have it set up nicely. Wish it wasn't a 3.5 hour drive though. Makes me have to get up and leave pretty early to make it to morning matches.

Trent,

Kidwell, Gazaway, Hubard and a few others built a state-of-the-art HP/BPCR Silhouette range at River Bend. But, nobody has taken the lead with respect to developing HP Silhouette matches there. Kidwell's a super guy. Maybe you and others should band together to get HP Silhouette going at River Bend. I can help with introductions if you and/or others are interested. The firing-line is covered and the range is very well laid-out. The JaJa Boys really did a top-flight job of building a world-class HP/BPCR silhouette range. If you're into smelling burnt charcoal (black powder), show-up for one of Kidwell's BPCR silhouette matches. The boys are mighty fine up there. I recon they'd even load-up a rifle for you to shoot...errr...become addicted to. Hey, no problem...I can shoot just one BPCR Silhouette match and walk away...no problem.... ....later..... Hello, my name is Trent, I'm a BPCR SihouetteAholic. Give Kidwell a call. His number is on the RBGC site.

[DanDeMan]

.....+1. Here we have "The Man" who has done the serious, long-term experimentation into all matters silhouette.

AJJ,

I test, therefor I am. ...a riff off of "Cogito ergo sum."

[DanDeMan]

.....Wish it wasn't a 3.5 hour drive though. Makes me have to get up and leave pretty early to make it to morning matches.

Trent,

The River Bend club allows dry camping on site. I'd be skedaddling up there the afternoon before a match. The 200-yd range is where most guys/gals dry camp in their SUV's, vans, 5th-wheels or motor homes. And, there are "comfort" facilities right there if going "rough." You know, sleeping in your van, car or SUV. Heck, when Kidwell holds one of his multi-day regional championships, the range's clubhouse has all kinds of "riffraff" bunked there. It does get a might "whiffy" with all those old geasers in there, though.

[DanDeMan]

Meine Damen und Herren,

To further the terminal ballistics discussion focused on ram-knock-down performance, here's some analysis and a picture of the 155-gr, 6.5mm Carturucio VLD's to get those salivary glands working.



First, I tested the 6.5mm behemoths in my 6.5-08 Hunter Rifle that sports an 8-twist, 26" long barrel. With RL-17 I can easily push those puppies to 2,800 fps. The estimated G1 BC, using JBM's simulator is in the 0.646 range at 2,804 fps. The load-testing I did with the bullets used up to 43.0 grains of RL-17. That powder charge produced 2,804 fps. Now, let's compare that to the 175-gr SMK launched from a 308 at 2,690 fps. Most would say that load would be "smashing" on rams. So, lets look at the recoil when using a 10 lb rifle; as well as wind deflection and terminal momentum. Here are the stats:

155-gr, 6.5mm Carturucio VLD launched by a 6.5-08:
MV = 2,804 fps using 43.0 grains of RL-17
Terminal Velocity = 2,070 fps
Terminal Momentum = (155/(7000 x 32)) x 2,070 = 1.43 ft-lb / sec
Wind Deflection in 10 mph crosswind = 3.0 MOA
Recoil = 9.1 ft/sec

175-gr SMK launched by a 308:
MV = 2,690 using 42.0 grains of VarGet
Terminal Velocity = 1,801 fps
Terminal Momentum = (175/(7000x32)) x 1801 = 1.40 ft-lb/sec
Wind Deflection in 10 mph crosswind = 4.2 MOA
Recoil = 9.6 ft-lbs/sec

So, with 5 % more recoil and 40 % more wind deflection, the 308 doesn't look so hot when its bullets hit rams. Terminal momentum is about the same between both bullets; and, the Cauterucio is a tougher bullet.

[ajj]

Dan:

Is it true that the hardness of the core is the key to bullet toughness on steel, or does the jacket design/thickness affect dwell time too?

[Bob Mc Alice]

This topic is mingled into two different threads and is a pain to follow.

Dan, you state "bullet toughness" and "tougher bullet" a couple of times reffering to Cauterucio bullets. His bullet list says he uses standard Sierra Match King jackets for the production of his VLD bullets. Those are not tough or as thick compared to Hornady Interloks for example. His core alloy needs to be soft enough to extrude wire and be final formed in the jacket. It must be very close to the same blend as the major manufacturers use. So, I read "tough" as more retained velocity /energy delivered to the target due to his VLD high BC design. Am I correct ?

[Snake]

McA---at the NRA show this last weekend the Nosler folks unveiled their new 168 gr 7mm hpbt competition bullet. Given the boat tail angle of Noslers and their jacket thickness I suspect they'll have a ram smasher on their hands ;) I think that Hornady might be coming out with a 140-150 gr 7mm A-max..shortly....their 162's work very well. That all being said Sierra and Lapua are the only two bullet manufacturers who support my regional....and that my friends should tell you who to support....the support the one that supports you.

[DanDeMan]

Dan:

Is it true that the hardness of the core is the key to bullet toughness on steel, or does the jacket design/thickness affect dwell time too?

ajj,

Both jacket thickness and core hardness increase dwell-time. I ran several experiments years ago with heat-treated 6mm, 107'gr SMK's. The properly annealed bullets, 1 hr at 400 F then directly quenched in cool, tap water, hit rams noticeably harder than the non-heat-treated bullets. But, all of the heat-treating experiments run with jacketed bullet showed groups opening up considerably. The cores need at least 2 % antimony to heat-treat. SMK cores have 3 % antimony, at least they did when I ran the tests.

[DanDeMan]

...... So, I read "tough" as more retained velocity /energy delivered to the target due to his VLD high BC design. Am I correct ?

Bob,

Carturucio makes his 7mm bullets out of 30-cal jackets, at least he did. The jackets get thicker when he swagges them down. I've got a stash of his 177-gr, 7mm VLD's from the 90's; em...bout 3 K remaining, same with his 141-gr VLD's in 6.5mm. And, he has made bullets with heavy jackets for me and others in the past. As a matter of fact, Pharr shot-up my last heavy-jacketed, 141-gr VLD's in 6.5mm a little while ago.

There's a easy, comparative way to check for bullet toughness. If there are freshly painted swingers in good shape, the tougher bullets will leave a small, shinny spot. Softer bullets will leave what looks like some gray spray paint. We noticed that years ago when comparing the 6.5mm bullets most of us were using in our silhouette rifles. The 139 Scenars would leave a bright, shiny spot about the size of a quarter. The 142 SMK's would leave a gray splotch. Same with the 108 Scenars vs the 107 SMK's. But, the recent Scenar bullets that I've tested are softer than the old stuff, say 1990's production. The first 144-gr, 6.5mm bullets I tested back in the 97 were tough, tough, tough. They were from production lots made in the early 90's. Neal Step had them for a reduced price because nobody wanted them. Man, they knocked the rams silly. But, after Jeanie Hershey and Tony Tello put together a 50K order so Lapua would make them again, they were nowhere near as tough as the old bullets. Those old 144-gr Lapua bullets made a rather different sound when hitting rams; a much louder ring compared to the SMK's. Lapua probably is making their jackets thinner given the cost of copper and zinc these days.

[Bob Mc Alice]

Lets face it guys and gals, we do not have a purpose designed bullet to push over steel rams. There are some that do a pretty good job at it though. All these match type projectiles are designed for the long range paper punching crowd. My nine twist sevens wont shoot the 175 MK very well, but will group the 175 Hornady Interlock plenty good enough for ram shooting. Increased recoil is the trade off. They are splended at dumping our club rams. I will just stick to my 168 SMK load and lose one now and then. Who cares, it is still fun to hit one.

I will try a box of those new Noslers when they come out.

[Jason]

Anyone cut open the Nosler custom competition 6.5mm bullets to check them out? I have a pretty decent stash of the 123 and 139-grain Silver Scenars, but might consider the Noslers when I run low at 1/3 off the price of the Lapuas if they make the grade.

[DanDeMan]

Jason,

Check out the below link to review Nosler's competition bullet construction. From my experience, the bullets will not be any better at toppling rams then Berger bullets. And, the Bergers have a substantially higher BC, so more momentum will be transferred to the ram for a given recoil suffered on the line.

http://www.nosler.com/Bullets/Custom-Competition.aspx

Now, check out the Nosler, Ballistic Tip bullet design in the below link. Note how much thicker the jacket is for the back half of the bullet. That is one tough bullet.

http://www.nosler.com/Bullets/Ballistic-Tip.aspx

Their AccuBond bullets have similar jackets; like the Ballistic Tips But, they might provide even more toughness due to the jackets being bonded to the cores.

http://www.nosler.com/Bullets/Accubond.aspx

[Jason]

Thanks for the info, Dan. I'll check into those. Before I go with those, I'd probably just work toward getting some of the 6.5mm 141gr bullets from Cauterucio. I still have enough of the Lapuas to last me through at least the rest of this year, maybe longer if work keeps getting in the way of my shooting.

[DanDeMan]

Jason,

Thanks for the "catch" on the wrong Ballistic Tip link. I corrected my previous post to reflect you help. Thanks dude. Oh, ask Bob for his heavy jacket version of the 141 VLD's.