.223, Berger 90 VLD's, and H-4350

[BoilerUP]

1:7 works just lovely at 2750fps with the 90gr Berger VLD for me...

 

[manitou210]

Interesting thread, just thought I would add some info on Powders for 223 shooting 90gr VLD Bergers in Fclass in the great white north Canada.
been shooting FTR for 8 years on my 3rd barrel app 3500 per barrel all 1/7 twist at 30",2 Tru Flite, Broughton,
started using;
VT 550 & 540 good speed & accuracy, major spikes in heat of summer, primers blown. very low ES 8 fps 2800 fps +
Imr 4895, IMR was very very accurate and good speed but never used it a match afraid of heat, blowing primers.
2520 was very accurate and crazy speed but the most pressure spikes in heat
I have tried many powders that work well with light bullets 50 to 55gr but these faster powders did not work well with 90gr bullets.for me
The two best powders for accuracy was VT N150, and Varget speed around the 2750 fps
I shot 15 rounds at 900m practice 3 where in bull 10" and 12 in v BULL 5" using Varget. N 150 very similar groups
I will not use any double base powders,hard on throat, and spike in heat, and hard on primer pockets.
my pet load for 300m is 80.5 Bergers Varget, at 2950 fps.I will use this load out to 600 y on very calm days with success but if wind gets bumpy the 90gr Bergers are best by far.
Hope this may help, love shooting the 223
manitou

 

[Laurie]

I'd agree with Manitou. My rifle never gave its smallest groups with N550, but MVs were excellent. VarGet and Re15 were the powders for me, and later N150 in a rebarrelled Savage LRPV varmint job with a Bartlein Medium Palma 26-inch 1-7.5 which made a really accurate and lovely to shoot 300-600 yard FTR rifle at modest MVs.

VarGet wouldn't give me as good MVs as Re15, but the latter worried me over temperature sensitivity even in our chilly summers in the UK - any hot spell would start serious primer cratering and my stress levels going up with every round fired. ~2,850 from VarGet, 2.910 from Re15.

We now have new (to us) Nitrochemie powders in the UK, the Reload Swiss range. These are the people who make Re17 (RS60) and all have the integrated deterrents that control burning rates for longer. RS52 looks perfect for 223 with 90s so I'm going to dig the original Savage based warhorse out with its quarter-inch freebore, also a second FTR rifle built on the LRPV action now in an Eliseo S1 chassis stock. This has been chambered with a reamer whose throat is derived from Bob Pitcairn's work in Canada with a much shorter 0.169" freebore, and should suit 80.5gn Bergers better than my earlier super-throated chamber allowing use of this bullet alongside 90s. I'm hopeful that RS52 will get me back up into the 2,900 fps node that seems to suit the 90s so well.

Although a 'high-energy' (infused nitroglycerine) propellant like N550 and Re15 (and with similar burning speed and specific energy ratings to Re15 at 3,900 KJ / Kg), RS52 doesn't seem as heat affected as Re15. I used it very successfully in 308 with the 168gn Berger Hybrid at 3,000 fps earlier this year and as a test left a box sitting on the front seat of my car in full sunlight in what for us was warm day (mid 70s) for around three hours before shooting it without any apparent adverse effects on pressure, POI, or group size.

 

[fm1947]

So I been reading that a lot of you are shooting 90 gr vld with a 7 twist, Berger has a twist calculator that shows a 7 twist will loose 4% in optimal performance, apparently that doesn't mean much you guys seem to be doing good

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

 

[Laurie]

Twist rate calculators often understimate the Sg value for HPBT form bullets as they're really geared to bullets that have the lead core all the way from bullet base to tip, as in BTSP, PSP, or FMJ types. Many HPBT match bullets have a considerable gap between the top of the core and the jacket tip and so manage better than they apparently should on the calculated Sg. The same applies to plastic tipped designs like the A-Max.

A 'classic' example of this phenomenon is Lapua's 0.308" 155gn Scenar, a very long bullet for its weight at 1.291", a greater length than that of 'traditional' 168-180gn models. Run it through Miller at 3,050 fps in standard ballistic conditions and here's what you get:

1 in ............

14" 1.02
13" 1.18
12" 1.39
11" 1.69
10" 2.00

So, a 1-12" barrel is required and under the latest thoughts, 1-11.5". Yet, go back some years and the 155 Scenar was the most widely handloaded bullet in GB 'Target Rifle' often over relatively mild loads of Viht N140 that would struggle to achieve 2,950 fps (50 fps or more less in many well worn barrels). Many of our TR shooters still used 1-14" barrels, hardly any with faster twists than 1-13", and yet these bullets and loads coped with competition shooting to 1,000 yards in our year round season. Take 2,950 fps, add a 1-14" twist barrel, throw in a chilly English winter's day (40 F) and high pressure on low lying Bisley (say 30.5" Hg actual) and the Sg sinks to a calculated 0.95, so the bullet shouldn't hit a barn door at 300, certainly never, ever stay in a 2-MOA 5-ring or 1-MOA V-ring at distances beyond 600 yards.

But they did! In fact, Russell Simmonds won early GB FTR championships with Scenars and 1-14" barrels, and probably still used a 1-14", certainly nothing faster than 1-13", when he won the World FTR Championship in 2009. Stick a bit of wire down a 155gn Scenar's meplat and it goes in a LONG way before it meets the core. (Not that I'd recommend anybody use these twist rates these days - I use 1-10" in 308 for everything including rifles normally restricted to 155s!)

90gn HPBT 0.224s are pretty similar to the Scenars in their construction - that's why 1-7" works, and as posted earlier, many believe the optimal twist rate is 1-7.2" or thereabouts. I found the now discontinued 90gn BT LR would perform superbly in 1-7.5" at only 2,600 odd fps and was never aware of any noticeable drop-off in BC.

 

[fm1947]

Laurie, thanks for all the info, I have a 7 twist barrel coming with a .252 neck, I have a lot of LC brass ready and weighted at 91 to 91.5 grs , only a .5 difference, the barrel is 26 inches and is a Shilen, I plan to or hope to shoot FTR at 600 yards that is all that is near me, any 1000 yard range is four hours away and really don't care for driving that much, I have some 82 gr Bergers coming but now I know a 7 twist will work I will try some 90s. Thanks!

 

[ericbc7]

Has anyone tried the new IMR 4166 with these heavy bullets? According to the press releases, they have addressed the temp sensitivity issue.

 

[savagedasher]

With a cartridge Length of 2.630 CFE 223 Winchester 760 Ramshot Big Game Will give you a few powders to look at also. CFE 223 would be my last choice. Larry

 

[manitou210]

Link to read robert Picairn on 223 on steroids, half way down

http://www.dcra.ca/Marksman/Marksman%20Summer%20Autumn%202012.pdf