Load workup with new 1-10 twist 243. N160 and 95 VLDs

[urbanrifleman]

First day out with the new rifle, new bullet, and new powder. Looking pretty darn good for a brand new combo. Why in the heck is no one shooting this? HAHA

40X action, 1-10 Craddock Precision barrel, Criterion blank 29" SAMMI chamber

N160
95 VLD Hunting moly jammed 20
42 node was 3050 and shot tiny
45 node akso shot tiny at 3250 FPS

This is not the upper node. The upper node is at 36.5ish and I did not load that high. Will next time I am going to narrow that node area. No pressure signs at all for the entire workup. Should be able to get almost 3400 FPS.

 

[steve123]

First day out with the new rifle, new bullet, and new powder. Looking pretty darn good for a brand new combo. Why in the heck is no one shooting this? HAHA

40X action, 1-10 Craddock Precision barrel, Criterion blank 29" SAMMI chamber

N160
95 VLD Hunting moly jammed 20
42 node was 3050 and shot tiny
45 node akso shot tiny at 3250 FPS

This is not the upper node. The upper node is at 36.5ish and I did not load that high. Will next time I am going to narrow that node area. No pressure signs at all for the entire workup. Should be able to get almost 3400 FPS.

View attachment 1044034 View attachment 1044033 View attachment 1044032

It's weird how high the 95's will go compared to 105's???

I got above 3500 fps in my 6x47L with 95 SMK and could have gone more. Bolt wasn't even sticky yet in my Mausingfield. That was with R17. .5 BC at 3500 is some serious ballistics, probably some serious throat wear too.

 

[urbanrifleman]

It's weird how high the 95's will go compared to 105's???

I got above 3500 fps in my 6x47L with 95 SMK and could have gone more. Bolt wasn't even sticky yet in my Mausingfield. That was with R17. .5 BC at 3500 is some serious ballistics, probably some serious throat wear too.

Why would more speed wear the throat? I mean more powder yes. Dan Whidden shoot 3500 with a 105 Hybrid and N160. He seems to do OK.

I agree I am not sure that people are taking this bullet seriously enough. At those speeds.

 

[Capt. Oblivious]

Well I might be wrong but more speed generally comes from more powder or a powder that burns with more energy. Now that should = faster throat wear. 105 @ 3500 even with N160 would surpise me if he uses a barrel for more than 1200 shots but its all consumalbles anyway.

Like the stock on that 243 of yours, is it a Bobby Hart?

 

[Laurie]

Why in the heck is no one shooting this? HAHA

One reason why not too many are doing it is that a 10-twist is on the feeble side for the 95gn Hunting VLD. Using Litz's measurements, the sample bullets he tested averaged 1.132" OAL.

Run that through Don Miller's Twist Rule spreadsheet and you get Sg (coffecient of stability) values of:

3,050 fps ...... 1.14
3,250 fps ...... 1.17

under 'standard conditions' (59-deg F air temperature; 29.92 inches mercury pressure at sea level).

I too have in the past worked up loads with bullet and barrel combinations that give Sg values around 1.1 and which shot a dream at 100 but then found they wouldn't hold 2 or 3-MOA elevation at 600 yards and up, or which gave quarter / third-MOA groups at 100 one day and 1-MOA plus on another.

If you're a couple of thousand feet or more ASL you might get away with it as each 1,000 ft additional elevation adds ~0.05 to the Sg and if you can get up to the 1.3 level and above the bullet should become a reliable medium to long range performer. BUT .... even so, you WILL lose BC value if significantly under 1.5 Sg. Bryan Litz gives this bullet an optimum twist rate of 1:8.6 and a minimum twist rate for stability of 1:9.6, the latter a bit pessimistic IMO, but he has to allow for people shooting on very cold winter days. (Ballistic Performance of Rifle Bullets 3rd edition by Bryan Litz.)

If you feed these numbers into Berger's stability calculator, you get

3,050 fps ................. 1.15 Sg; 11% loss of BC value
3,250 fps ................. 1.17 Sg; 10% loss of BC value

at the 1.3 Sg level if you can get there on altitude, you still lose 6% of Berger's claimed 0.239 G7 BC rating according to the program.

The company's 95gn Classic Hunter Hybrid bullet is a shorter design so can manage on a slower rotational speed. Even so, Berger recommends a minimum 9.6 twist barrel. In a 10 at 3,250 fps, its Sg runs at 1.37 in 'standard conditions', and Berger says that drops its BC by 4%.

(The VLD minus 10% BC and the Classic Hunter minus 4% actually have the same effective resulting BC of 0.215. However, with a near 1.4 Sg, the latter will likely behave much more consistently in a range of atmospheric / weather conditions and at all distances.)

 

[urbanrifleman]

Then shoot an 8 twist. Still a great combo. And I will be at 3400 when I get done.

 

[urbanrifleman]

Trying the 88 vld fb next.

The 70 tnt is already shooting very tiny too.

 

[Zero333]

88gr berger FB might blow up or become erratic. I shot 80 FB in a 8" twist and all was amazing in the deep freeze temps. Once it got closer to 30 f, groups started opening up, and 20% of the bullets never made it to the target at 200m. Just broke apart.

Kinda sucks because they shot so consistent small groups.

Good luck.

 

[Laurie]

Then shoot an 8 twist. Still a great combo. And I will be at 3400 when I get done.

8 twist is the way to go. 10 is very limiting, light match and varmint bullets mainly, mostly low BC designs.

 

[urbanrifleman]

8 twist is the way to go. 10 is very limiting, light match and varmint bullets mainly, mostly low BC designs.

For a long range match rifle use only, yes. 1-10 is not what I wanted. But since I got it I thought I would do some workups until my Bartlein 5r 1-8 gets here.

 

[Laurie]

I'm doing some load work-ups on a 24-inch Howa 1500 Varminter in 243 later this year to explore what's available for the many such 243 owners who'd like to do a bit of F-Class or suchlike. It is pretty frustrating finding useful bullets that suit the 10 twist, a real shame that most manufacturers didn't move to around 9 as per Remington. I do have a good selection to try including several Berger flat-base models up to the 88gn HBC, so it'll be interesting to see what it'll do. A much underrated cartridge I always reckon.

UK police forces used 243 a lot many years back after British Army experience in the Irish 'troubles' of the 70s and 80s where the standard 7.62 NATO FMJ round acquired a reputation in short-range urban firefights of punching through cheap Jerry-built housing walls and injuring or killing innocent citizens in their beds or sitting watching TV! So, the mainland police went for 243 marksman type rifles firing standard 100gn PSP deer ammo. (They've now forgotten all about this and returned to 308 Win.) Around 15 years ago, I bought one such ex-police Parker-Hale M87 - a really impressive rifle designed for military sniper and police use - and used all sorts of factory ammo and handloads in it on the ranges. There was a great deal of elderly surplus (white and orange boxes - had to be ancient!) Sako 90gn FMJ ammo around in the UK at the time which made it very cheap to shoot this rifle. With a lot of factory deer ammo, I got very good results up to 300 yards, started to see things slide downhill at 500, and struggled at 600. The Sako 90s were much better, but still not as good as would have been expected from the M87 with a 308 barrel on.

Although I had a lot of good times with this rifle and came to be quite a 243 Win fan, I thought the 243 and its ammo were inherently deficient as range numbers at the time. With hindsight, I'm now convinced the 10-twist was the culprit. So, now it's a case of finding things that will be at least reasonably stabilised (1.3 and above) in the Howa and see how they do. As I said, a bit of a challenge! As an example of the constraints involved, some years back, Bryan Litz designed the .243 87gn Hunting VLD for Berger and it was launched as a dual-purpose deer / match bullet for standard twist 243 rifles. Since then, the bar has been raised so much as to the minimum stability conditions that should be achieved that those aims aren't achievable (in theory anyway), and Berger no longer advertises it for this purpose. At 3,300 fps it computes at 1.34 in standard conditions in the 10 twist, so it always was going to give its best as a high-ground / warm weather number at longer ranges, but in the days of 1.4 Sg being seen as optimum, 1.34 was close enough to allow a nice pointy design to be produced. (That's another model I've acquired - looking forward to trying it here, although I'm not a great VLD fan.)

Anyway, carry on having fun .... and barrelmakers / gunsmiths love customers who shoot hot 243s, so you have plenty of friends with you.

 

[JaoeyP]

I started playing with a Howa 1500 this summer, trying to push the envelope with bullets and the 10" twist rate. I was getting about 1/2" groups with 95gr Sierra Match Kings at 100 yards and had gotten 2" groups at 380 yards. I had posted on here about some of the different loads idI been trying and had more than a few comment or PM me about my loads being marginally stable. I thought it was all guffaw. Fast forward to this winter. Took my 95gr SMK pet load to the range and it was not grouping. It was so bad I was convinced it was my scope. Swapped scopes, same results. Noticed a louder smack on the target board. Closely inspected my targets and found the holes weren't round. Went through the numbers on the JBM stability calculator and adjusted for winter temperatures. Stability number had dropped below 1.0.

I believe the 10" twist will do best with bullets that have a BC of around .430 or lower; above that to around .49 the bullets will be marginally stable, and beyond .50 they likely won't stabilize at all. A lot of guys don't want to mess with with a load that shoots great one day, but falls apart the next and that's why more guys don't run 95gr VLDs in a 10" twist. For me, messing around, experiencing the failures and success, and pushing the envelope is half the fun!!

If you want to check out what a 10" twist Howa can do with a 95gr VLD, check out Mark and Sam After Work on YouTube. They were my inspiration for buying a Howa and tinkering with it in 243.

 

[urbanrifleman]

I shot one of my 600 yard matches with 80 grain Bergers in my 6BR. It shot quite well. I could shoot the 90 grain Lapua or the 88 grain Berger in a pinch. But truth be told when my Bartlein gets here this is going to be for 70 grain TNTS at warp speed