Re: 6-284 long range antelope load
Interesting information, sorry I have not replied sooner, been a little crazy in the shop.
I guess you have to decide what is the most important to you for load characteristics.
As an extreme range shooter, meaning medium range shooting is +800 yards and serious stuff starts at 1000 yard and beyond.
I look first at E.S. numbers. For this type of shooting, 30 fps E.S. is on the top end of acceptibility. I much prefer to get then in the low teens or single digits.
Your rifle is not designed for this style of shooting. It takes advantage of the brute horsepower of the 6mm-284 round to drive light to medium weight bullets very fast.
I would say that if I had your rifle, I would say 600 yards would be my range limit using it with the 87 gr V-Max.
Please understand this is not a put-down to your rifle, 600 yard shooting is serious work that needs the best equipment available and precise machining and ammo.
It is the bullet that places your range limitations as well as load characteristics such as basic accuracy and consistancy.
Of the loads you listed, I would concentrate on the H-4350 load. 3650 fps is smoking fast. Remember you are getting 22-250 Rem velocity using a 55 gr pill but you are driving a 22 gr heavier bullet. This is siginificant.
Now for the bolt lift resistance, when do you feel this resistance? Is it on the first 1/3 of the bolts rotation when you start to lift the bolt from the locked position or is it when the extractor cam on the bolt handle engages the cam on the receiver.
If it is the extractor cam you will feel it at the very last amount of movement in the bolt life.
If your running the pressure to high, you will feel the bolt lift resistance increase from the very start because the case is pushing very hard back against the bolt face after firing.
If the initial bolt lift is normal and only the last part has a little resistance, this means that your cases are tight in the chameber but not against the bolt face.
Any round such as the 6mm-284 with its minimal body taper is going to be slightly harder to extract or at least to initially pop free of the chamber.
It could also be that you have a burr on your extractor cam either on your bolt or receiver. If you do, take a shone and carefully smooth the burr out and then use a high quality Moly grease between these surfaces to prevent or reduce further gauling.
This is a common problem with Rem 700 actions but an easy one to fix. I just range tested a 22-6mm AI this morning that I built that had the same problem. It is not generally a pressure problem but a mechanical problem like the burr presents.
That said, if you can not get at least 4 firings per case without the primer pockets getting looser, you need to reduce your load until youcan get this.
As far as the load testing, I would certainly go with the H-4350 for further testing.
What primer are you using. Sometimes trying a cooler or even slightly hotter primer will drop E.S. a measurable amount.
Also, play with the seating depth and this will ofter tune group size and consistancy.
Finally, again with the bolt lift. In a round like the 6mm-284, I recommend to my customers that after every 5 shots or so to either get new brass or have your cases properly annealed to restore their elasticity.
With the powder volume and heat generated by the 6mm-284, cases get work hardened pretty fast. This make the brass stiffer and it will not contract down after firing. This will create a false indication of high pressure as well and can often result in a shiny ejector mark on the case head.
This is one reason I do not recommend tight necked chamebers in such high intesnity rounds, most will not anneal theor cases after 5 firings and then the brass is really to hard to perform well..
Anyway, I would load up 15 rounds of that H-4350 load and shoot either 5 three shot groups or three 5 shot groups and average them to see what the load will really do. Also, a 15 round string will really tell you how consistant the load is also.
For your purposes, 72 fps E.S. is alot but not unusible by any means. I have a Ruger M77 VT that I rechambered to 22-250 AI that averages 110 fps spreads with its favorite load of H-380 under the 50 gr Ballistic Silvertip. Still it is a 1/4 moa rifle at 100 yards and will easily hold 80% hit ratios on P. Dogs out to the 400 yard line. This is fine for this rifle as it will not be used for anything much farther then this anyway.
Always try to get E.S. in the sub 30 fps range but do not give up on a tight grouping load for teh sake of E.S.'s. Especially for a rifle used at conventional varminting ranges.
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