Rmr 75gr bthp over rl15

[Blue68f100]

Taking large jumps (0.5gr) on a small volume case you may jump completely over the node. A 0.3gr step would be a better choice. I don't like jumping more than 1% of max. You didn't mention what brass mfg your using, hopefully all the same head stamp.

 

[Big-bore-bob]

You didn't mention what brass mfg your using, hopefully all the same head stamp.

They're all Lake city 5.56 brass, I sort all my brass by headstamp. The reason I chose .5gr increments was the most common pet load I've come across in my research was 24gr rl15 under a 75gr hpbt, so I expect that's where I'll see accuracy. However I also wanted to see what the velocity spread across a larger load range looked like with my components, in my gun, for comparison to published data. I chose to go as far as 24.5gr to see if any pressure signs pop up at the upper range of the data set.

 

[JEBruns]

I believe you have that reversed. The eldm 75 will not load mag length,

That's what I said.

 

[Big-bore-bob]

Results are in for the RMR 75gr bthp with rl15 test. Platform: radian model 1 18in. 10 shot group averages.
Lake city 1x fired brass
Rl15 powder
Rem 7 1/2 primer
Altitude 4400ft
Temp 60f
Barrel length 18in

22.5gr, SD 23.7, avg 2511, es 79, 1.18 moa.
23gr, SD 13.8, avg 2578, es 41, 1.79 moa.
23.5, SD 18.9, avg 2639, es 67, 1.71 moa.
24, SD 19, avg 2698, es 65, 1.52 moa.
24.5, SD 25.5, avg 2730, es 98, 1.93 moa.
The 24gr load was definitely the best. I may have thrown the three fliers as there's 7 rounds in a .90in group. How should I proceed with the next test?

 

[conan32120]

Do those holes look slightly keyholed?

 

[Big-bore-bob]

Do those holes look slightly keyholed?

Not to me, but I know nothing. Target had a particle wood backboard. Its a birchwood Casey shoot n see target with the peel off backing still on. I didn't peel it, just stapled it to the plywood.

 

[Laphroaig]

The 24gr load was definitely the best.

That's my load too, albeit w/ Hornady's. I've never shot mine from the bench, but that load is capable of cleaning the 300 yd. MR-63 target which has a 2 MOA 10 ring, shot prone w/ a sling.

 

[TonyAngel]

Results are in for the RMR 75gr bthp with rl15 test. Platform: radian model 1 18in. 10 shot group averages.
Lake city 1x fired brass
Rl15 powder
Rem 7 1/2 primer
Altitude 4400ft
Temp 60f
Barrel length 18in

22.5gr, SD 23.7, avg 2511, es 79, 1.18 moa.
23gr, SD 13.8, avg 2578, es 41, 1.79 moa.
23.5, SD 18.9, avg 2639, es 67, 1.71 moa.
24, SD 19, avg 2698, es 65, 1.52 moa.
24.5, SD 25.5, avg 2730, es 98, 1.93 moa.
The 24gr load was definitely the best. I may have thrown the three fliers as there's 7 rounds in a .90in group. How should I proceed with the next test?

Honestly? I'd call it a day, in terms of load development. Maybe tweak bullet seating depth /crimp a bit just to see what it gets you. I was always anal about loading for an autoloader. The possibility of bullet setback during chamber was always on my mind. I ultimately started crimping with a Lee factory crimp die.

It looks like you're getting results that will satisfy your needs. The 10 round groups you're getting aren't shabby at all.

 

[Peakbagger46]

Not the exact bullet, but Rel 15 has proven unexpectedly accurate with my chrome lined AR 16” barrel. Groups are 50 yards (sighting in the low power scope for a 50/200 zero).

While 23.5 grains has proved safe for me, be aware that going up towards max has shown pressure signs in hot weather in my experience.

Hope this helps. When I run out of 15 I plan to switch to VARGET but only for the temp stability.

 

[Big-bore-bob]

Hope this helps. When I run out of 15 I plan to switch to VARGET but only for the temp stability

I'll definitely keep an eye out for pressure signs as the weather gets warmer. I left the rounds in the sun today during testing to warm them up a bit. I'll try playing with the crimp a bit, I'm just barely kissing the case mouth, so ill try a little bit more on the next test. I just barely got light ejector swipes on the case heads at the 24.5gr charge ( less than factory m193) so I think ill be ok pressure wise as the temps begin to rise into the 80's if I stick with the 24gr charge. Thanks for the replies!!!

 

[AJC1]

Not the exact bullet, but Rel 15 has proven unexpectedly accurate with my chrome lined AR 16” barrel. Groups are 50 yards (sighting in the low power scope for a 50/200 zero).

While 23.5 grains has proved safe for me, be aware that going up towards max has shown pressure signs in hot weather in my experience.

Hope this helps. When I run out of 15 I plan to switch to VARGET but only for the temp stability.

View attachment 1205996

At one time I might of said try 15.5 as it's their new temp stable formula, but I've never seen it on the shelf. A lot of guys like ar-comp for that reason as well, but the price on that powder has gone insane.

 

[Laphroaig]

Alliant claims "consistent at all temperatures".

 

[IALoder]

The 24gr load was definitely the best.

Right at 24.0-24.1 rl15 with the 75gr Hornady BTHP was my load in LC brass as well. I'd do a little detail work around that 24.0.

 

[ms6852]

Hi all,
So I'm diving in to reloading rifle cartridges for the first time. I just bought a radian model 1, 18in ar15. I've just ordered some rem 7 1/2 primers and sourced 5lbs of rl15. I plan on using once fired lake city brass. I would like to use rmr 75gr bthp bullets because of the incredible price. Does anyone have experience with this component combo? I'm looking for sub moa accuracy for coyote and target work. I have manuals that list this powder with a 75gr bullet so I don't need load data, just curious about personal experience with this bullet and/or powder. Thanks in advance for any replies! Happy shooting.

All I load on my AR15 are 75gr bthp hornady performance and I use RL15. I like it a lot. My ar is a RRA with a 20" heavy barrel. The shot groups were done at 200 yards. Here are a couple of pictures with different loads. When I moved up to 23 grains the group opened up, more than it did at 20 grains.

 

[DMW1116]

I’m may have to try these after all. I have several 69 grain RMR to load first though. I may load another test batch with Match Rifle, or at least a test group with my previous best load.

It’s a little slower than I’d like if my math is correct. It’s high 2600s to low 2700s. In that range I’d be better off with 75 grain bullets. I could run it up into 5.56 loads but I generally try to avoid that. My rifle does seem to like the 75 grain Hornady, though IMR 4064 is currently out of my price range, hence the Match Rifle.

 

[Buzznrose]

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[Big-bore-bob]

Well I just tested my new batch of reloads same specs except an eighth turn more on crimp ( i pulled a bullet and theres no crimp ring on the bullet), 24gr rl15. My friend gave me some pointers on bench shooting a gas gun and I achieved a sub moa group! I put in an order for 500 hornady match 75gr bthp so I'm planning a head to head comparison in the very near future.