RPR .308 loading.
This is a discussion on RPR .308 loading. within the Reloading forums, part of the Sniping Related category; Hi, I'm am new here and new to long range shooting, also new to loading so I thought I would pick the brains of those ...
RPR .308 loading.
Hi, I'm am new here and new to long range shooting, also new to loading so I thought I would pick the brains of those who have been doing it. I have recently decided to load my own ammunition and match it to my rife, a ruger precision in .308 with a 20 in 1:10 twist. This is the first time that I have done this and with all of the information on the internet it can be overwhelming considering it can be very contridictive.
So I'm wondering where to start
1 - what supplies? Powder, bullet, primer.
2 - what order to do things? Such as what to teat first. Bullet weight, powder amount ext.
3- what fps should I aim for?
My goal to to be able to reach 1000 yards. Thank you in advance for your assistance.
Well then . . . welcome to the rabbit hole.
Originally Posted by GLT86
I've been reloading for my Gen2 RPR .308 now for 3 years. Switched out the factory barrel after 3700 rounds (not because it needed replacing, but because I just wanted a better barrel) to a 26" Krieger barrel, which I now have over 2,000 rounds down this tube.
A lot depends on just how often you're going to be shooting at 1000yds and/or what you'll typically be shooting at. In either case, a good affordable bullet is a 175 gr SMK or the Berger 175 hybrid. The SMK is a good bullet and a little more affordable than the Berger. The Berger has a small advantage for shooting very long distance.
As far as powder, Varget is the most popular, but H4895 does really well and I actually come to like AR-Comp the best. I've used Federal and CCI primers and find that CCI200 do really well with these powders in this cartridge.
2670 is a nice target velocity for a .308 shooting out to 1000 yds. But, that's hard to achieve with a 20" barrel. To get there, you'd be using some pretty high pressure loads. 1000 yds is certainly doable with less velocity and you should be able to do just fine with a velocity round 2500 fps with a 175 SMK and 42.5 gr Varget. Just keep in mind that you'll have to test various loads to find what works best in YOUR gun. Though you and I have the "same" rifle, the loads can be (and most likely are) different.
If you're shooting steel at 1000 yds, you might try some Federal Premium Gold Medal ammo (they come with either SMK or Berger bullets) and can do well. If I recall correctly, the MV for them is at 2600 fps.
In terms of reloading equipment, a lot depends on how much you have in your pocketbook to get started. You may have heard the expression "buy once, cry once" which says not to be cheep and buy things you'll soon come to replace with a much better products to get the results you really want. When starting out, I'd say it's best to get one of the best resizing and seating dies. Also, since getting accurate powder measurements is so very important, you should consider something like the Frandford Arsenal Intellidropper. I feel there are some places you can cut corners on, like for cleaning your brass you can go cheep with a wet tumbler from Harbor Freight Tools. A tool for trimming, chamfering and deburring would be like the Trim-It 2, which does a great job and fast. At least one good caliper is important to have.
Well, hopefully this gives you some good ideas. There's a lot of good experience reloaders around here that can answer any question you might have. I've learned and continue to learn from them.
Thank you. That was a great deal of help. I will mainly be shooting out to 600 yard for now but plan on doing some 1000 yard in the near future so I wanted to develop a round that was ready to be tweaked once I get there rather than starting over. One more question, what is the best order in the development of ammunition? Should I fist focus on the charge, OAL or the bullet?
Well, first . . . you really should decide on what bullet you want to use. I'd recommend going with a 175 SMK. They work well for what you state your use is for and rather easy to tune.
Originally Posted by GLT86
Starting out with the development, you'll want to decide on just how you want to seat the bullet (determining the COL you want to use) and that can be different depending on the bullet you choose. SAAMI spec for .308 is at 2.800 for the likes of a 175 SMK. So, you may want to start there. Eventually you want to take a measurement of your throat so you can determine just how far out you can seat the bullet and find some distance in between that give you your best results (maybe something like .020 off the lands, which in my factory barrel was once with a COL of 2.837 for a 175 SMK). It will be different for different bullets. For example, using a 175 Berger will be very different due to the difference in the bullet specs.
Then, decide on a powder to use. The most important thing in reloading will be getting the right powder charge AND being able to get as consistent charge/accurate charge in each case.
When reloading, we much keep in mind that whenever we change just one thing it effects what we might need to do with some other element of the reloading. As an example, having a longer COL increases the interior volume of the case (case capacity), which will decrease the pressure when a round if fired. If one want to maintain the same pressure, one would then have to increase the powder charge to compensate. This is just to illustrate the relationship. We go through a process of changing the powder charge and/or the COL as we look for an accuracy node that gives us accurate and precision POI's (along with other small details in case preparation).
Do you have a reason why you would pick the SMKs over the berger?
He said it. Price. Bergers always cost an extra 20% for some reason. You will not get a 20% increase in performance for sure. Another thing to consider is a 6.5 CM barrel. You would need to change nothing else and now you have a 1,500 yard gun instead of 1,000. It's not necessary but the big difference between the two is the throat design. 308 can vary all over while 6.5CM is cut very uniformly making seating depth much less of an issue. The reason you want to adjust seating depth on a round like a 308 is the throat is so wide and variable. This causes the bullet to wobble as it transitions from the throat to the lands. So you look for a seating depth where the bullet is already touching the lands to eliminate this. Think of the 6.5 CM as having a much tighter funnel that does much to keep the round concentric with the lands. This largely eliminates throat to land transition issues and hence explains the inherent accuracy of the Creedmoors in so many rifles with so many varying loads.
BTW - I think he's talking SMKs not TMKs. The TMK is a different design that is much more sensitive to seating depth. it too is a great bullet once you get the depth correct. Just understand it has a different secant / ogive setup that makes it a different animal.
Last edited by ChuckP65; 11-20-2019 at 06:06 PM.
Yes, as mentioned . . . the SMK's can be quite a bit less expensive than Berger's. If one takes a little time and effort, good deals can be found for SMK's, like I picked up some SMK's on sale for $157 per box of 500. Another reason is that's the SMK's are a little more forgiving than Berger's where it just easier to get a satisfactory load. While Berger's can provide an edge for precision shooting at 1000 yds, until one become somewhat of a skilled precision shooter, the difference isn't likely measurable. So the price and ease of tuning a load makes me lean a lot towards the SMK's. PS: As mentioned by ChuckP65, TMK's, with it's design are quite a bit harder to find a good load.
Originally Posted by GLT86
He also mentioned considering changing out the .308 barrel for a 6.5 CM barrel. There's a lot of good reason to go with a 6.5 or even a 6.0 caliber. Before I changed out my factory barrel, I considered that. But, decided to stick with the .308 as I don't shoot competitively and since I do shoot a lot the .308 barrel can take a lot more pills down the tube than a 6.5CM. Depending on one's loads, one should be able to get 5000 - 7000 through a .308 (a few people have reported getting over 10,000 through their .308). For a 6.5CM, you looking at something like 2000-2500 (maybe 3000 if your lucky and maybe on 1500 as many have reported, though the latter usually involves the hotter loads). I think most serious precision shooters will tell you that a barrel is a consumable like your other consumables for this sport. So, be prepared for that.
One of the nice things about the RPR is that it's rather easy to drop in a new barrel as the rifle and barrel are made that way - just have to have a couple simple tools like the go/no-go guages, barrel vice and wrench. It took me about 20 minutes (I tend to be quite mechanically inclined) to swap mine out and it was the first time I ever did that kind of thing and my RPR has been working just fine now for over 2000 rounds.
I have a friend that has over 4000 rounds through a 6.5 barrel and it still shoots sub 1/2 moa.
Berger bullets have a distinct edge over smk’s. The difference may not be seen in a factory barrel or by a novice shooter, but the Berger bullets are better quality and more consistent. That said, SMK’s are not bad either.
Do not load your bullets to the lands...even in 308. This is not ideal and can produce dangerous pressure spikes. You want about 0.010” jump, and you need an accurate way to measure that jump as well. 308 will do just fine with a little jump. Many factory rifles have throats so long that massive jump is necessary yet some of them still shoot pretty good.
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I use 175 smk's myself. I get sub 1/2 moa at 200 yds with my factory rem adl barrel, surprisingly enough. 40.7 grains of imr 4064, coal of 2.875" which is still pretty far off the lands, but the max in a pmag. Keep in mind, bullet weight/performance will rely heavily on your barrels twist rate. The faster the twist, the heavier the bullet. Ideal twist for a 175 is 1:11.25. My barrel is a 1:10 but still loves the 175 smk. Even a 168 starts to spread an unacceptable amount. Happy loading!
I like using 155 smk behind 47gr of varget for 1000 yards. Get them going around 2950fps and they are flat shooting bullets. But since I'm running low, (maybe 5 lbs left) I've switched back to 175s. 42grs of 4064 leaves a nice little hole. I also get away with seating mine out to 2.9 since my rifle is a m24. I measured mine at 2.908. Leave about a .008 to jump. Over good loads. I'll be trying these loads in my savage 10 this weekend but obviously seated to 2.8. Both savages I own are to spec which I crazy to me coming from my m24. Have to seat bullets at 2.798 to be able to close the bolt easily. Picture is 42grs of 4064 with 175smk at 2.9oal out of my m24.
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