RL 15 Mistake

[CoverDog]

I have been using Varget in a 6mm Norma Br with what I would consider good but not great results. Mid to upper .2's and low .3's These are ONLY 3 shot groups @ 100yds. I was wanting to see the crono results.

So here is the mistake...Bought RL 15 yesterday and loaded up 3 shots ea. of SMK 107's, Ber. 105 VLD, and 105 A-Max with both CCI 450's and BR4's. Was starting with 30.2gr and then going to 30.5gr with each. After the first shot this morning I realized,looking at my notes) I loaded 31.2 & 31.5 not 30.2 & 30.5.

No real pressure signs, primers were not cratered, nor flattened had nice rounded edges looking through a jewlers loop. All specs were within acceptable ranges when mic'd. FPS were 2925. So I continued with the 31.2 loads. Checking each case after every shot. DID NOT shoot the other 31.5 load.

The group with the 31.2 and Bergers/BR4 shot one hole at .110" Crono readings were as follows:

High 2935.8
Low 2926.1
SD 4.8
CV 0.16%
MAD 3.4
CV 0.12%
Avg. 2931.1
ES 9.7

I plan to load down from here to see what we get, but without pressure signs would you continue to shot this load?

 

[Forum Boss]

Tough question. Your ES/SD and accuracy are awesome. Your load is similar to what some guys are running in their 8-twist 6BRs with a long throat.

On the other hand, a max load of RL15 in my barrel is about 30.5 and that will show ejector marks on a hot day.

2900-2930 has proven to be a very accurate "speed zone" for a lot of guys.

I would measure the cases and watch carefully for stiff bolt lift etc.

I would also try to chamber the fired cases and see how the bolt closure feels.

Also it would be useful to know your barrel type and barrel length. Broughton 5Cs in particular are known for needing more powder to reach certain velocity levels.

I agree not to try to 31.5, but I would try 30.8 and 31.0.

If you're getting about 10 fps per tenth of a grain, that's pretty typical, so 31.0 should be about 2910 fps.

Keep in mind that RL15 IS temp sensitive. Keep your loaded rounds OUT of the SUN, and don't let them sit too long in a hot chamber. I would drop the load 0.2-0.3 grains if the outside temp will be 85+ degrees F.

 

[CoverDog]

The gun is a bone stock Savage F Class 8-twist 30" barrel. I have spent the last week trying to do a proper break-in. 157 down the tube so far.

I measured the chamber at 1.581 with a Sinclair chamber lenght gauge. Bullets were seated .015 into the lands.

I had a couple of cases with slight ejector marks but those were with the SMK's. I had even better crono numbers with the A-Max/BR4 SD 2.2, MAD 1.7, ES 4.3, avg 2927.9fps but nothing to speek of in accuracy.

Today temps were in the mid 70's with low humid.

Yes, I just loaded some in 30.6, 30.8 & 31.0 and hope I can get out on Wednesday.

 

[jb1000br]

Imagine that...that is the exact performance mine gets with the same load...works alright at 1000...

JB