And If Laurie is reading this, he may have some input on the
Long Rifle powder.
That's Lovex S065, a straightforward single-based tubular grade. We have it in the UK under that name - Shooters World imports it and packages it up as its 'Long Rifle' grade in the US. Burn-rate / applications wise, IME it falls between VarGet and H4350, probably a little nearer the VarGet end. I would say to forget its apparently suitable stablemate Lovex S070 (Shooters World 4350) as it is much slower burning than the other 4350s and although very consistent, failed to produce H4350 level MVs, or anything like. In a 60gn case with 140s, I'd expect similar results - still who knows?
As others have said, I'd imagine the 4350s should suit this particular 7mm application. The field is becoming crowded too with powders claiming to do the same job (the Creedmoor effect where every second person has to have H4350 for this cartridge), although many of them don't.
I tested S065 / Long Rifle as an H4350 alternative (alongside another dozen possibilities) a couple of years back in 7mm-08, long-throat chamber, 160gn Sierra TMK, and it did very well. The others that did well in these tests were Viht N160 and Reload Swiss RS62 (not available in the US). For the larger case 284 with 180s, Viht N160 and 165 are widely used here since the loss of IMR and H4831. Those trying N555 report good results in this application, and I've had excellent results from it in 300 SAUM with 200s, a classic 4350 application.
http://www.targetshooter.co.uk/?p=3483
http://www.targetshooter.co.uk/?p=3624
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Viht N150 and N160 are both noticeably faster burning than burn rate charts suggest. Their 'High-energy' forms with infused nitroglycerin, N550/560 are marginally slower than their N100 base grades. I suspect that N560 might be a tad too slow burning for the 7mm wildcat, although people use it here in 7mm-08AI match loads - but that's with heavier bullets than 140gn. N165 is definitely too slow burning for this application - it'll perform well but won't produce the MVs. It usually runs significantly compressed charges in the 284 despite its 66gn capacity case even with 175/180gn bullets seated well out.
N555 doesn't sit in the middle of the N150/160 gap, rather appears to lie closer to N160 based on powder charges. It might do well in the wildcat, likewise the very much faster burning N550. (If modelling N550 in QuickLOAD, the default values are way out as a result and if you believe the calculations and potential charge weights, you can easily overload things to dangerous levels, especially as when it pressures out, it does so very rapidly over small charge increases.)
