Posted: 4/26/2016 8:41:49 AM EDT
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I'm developing a load for my MVP Varmint 24". Purpose of this is generally for cheaper long range practice, and general skills building. Max distance would be 700 yards, with most use at 500 yards or less. I did a ladder load test of 75gr Hornady BTHP and found an accuracy node at 22.7gr of H4895 as well as at 24.3gr. The velocity of the 22.7gr load was very similar to factory Hornady 75gr Match (2680 vs. 2659). The 24.3gr load came in with an average velocity of 2882.
So, do I stick with the lower velocity and keep brass life up, or push the velocity to help buck wind and drop a bit better? |
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If you don't have any pressure signs at the higher velocity, then run a series of 5-reload cycles on the brass.
If the primer pockets are still good to go, then your load is not overpressure and you can use it rather indefinitely with little brass life consequences. |
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Quoted:
I'm developing a load for my MVP Varmint 24". Purpose of this is generally for cheaper long range practice, and general skills building. Max distance would be 700 yards, with most use at 500 yards or less. I did a ladder load test of 75gr Hornady BTHP and found an accuracy node at 22.7gr of H4895 as well as at 24.3gr. The velocity of the 22.7gr load was very similar to factory Hornady 75gr Match (2680 vs. 2659). The 24.3gr load came in with an average velocity of 2882. So, do I stick with the lower velocity and keep brass life up, or push the velocity to help buck wind and drop a bit better? Was there any chance you tested group size after you found those two nodes? That velocity difference would be considered a big advantage in many games including F-Class and Service Rifle. If the group size of that faster load is good, I would run the case life test and go for it. The mere fact you are running a 223 is enough of a disadvantage as it is without adding to the challenges. Even with the faster load, most rigs on the line will shoot inside you due to superior cartridge designs. So you will definitely be learning to dope wind in practice with this rig. I would also consider RL-15 with a Rem 7 1/2 primer. Here are some known good Service Rifle recipes for a perspective using a 20" bbl. http://www.radomski.us/njhp/cart_tech.htm The real key here is the size of your intended target. Are we talking about a defined X-ring, or a varmint? |
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I don't have a specified target. Mostly it's meant for steel and practice/competition for precision rifle events. This rifle may be put into service for coyotes, but that's probably the extent of it.
Thank you for the service rifle recipe link. Given some of the data in there, I may stick to my lower charge. I'm using BR-4 primers as I have a few thousand of them already. I'm using LC brass, though I haven't gone so far as to sort them by volume, weight, or even year at this point. A few points of data that were close to where I'm currently at from that resource as well: They list a 77MK w/ H4895 @ 23.0gr and a velocity of 2665. Mine was 22.7gr @ 2680 with the 75gr BTHP Hornady. They also list the 75gr Hornady ideal MV at 2650 with 22.5gr of H4895 as being ideal for 200,300, and 600 yards. Given that I'm running a 24" barrel vs. the load data reference of a 20" barrel, I think I've come to a natural similar conclusion as the service rifle guys. I'd be curious to run these through my 20" AR to see if the number match even more closely. |
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I could suggest you don't need to, but then to really learn this stuff you have to balance between reading trustworthy material and getting your own hands dirty.
Remember those service rifle bbls are generally the quality of a CL or WOA. If your is about that kind, you will get similar results. I would also suggest you grab a sample of Black Hills loads as a reference baseline to use for debugging purposes. Their 223, 5.56, and .308 match loads are pretty decent stuff and good to have around. BTW, a gong or coyote can be a small target at 600. I would recommend some of the books from Applied Ballistics if you have not already been through those trade offs. You will learn quickly how to trade between group size and speed in order to beat the wind. |
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Try some IMR 8208 XBR, I would guess that you would get another 100 FPS or more with that 24" barrel. I shoot it in my 24" Tikka with a 75 Amax and am seeing velocities in the mid 2800's without a lot of pressure.
With that bullet it makes for a fun 1000 yard load but they won't fit in a MVP/AR mag. You can go that far with the 75 BTHP but it isn't nearly as good in the wind. |