Hey. It's me. The guy who can't get decent ES/SD from his 6 SLR

[Capt. Oblivious]

Montana im a bit pressed for time so didnt read al the replys but in my SLR i found it wanted a bit more neck tension than id usually run. Im shooting the equivalent to H4831in my SLR with Lapua brass and Molyd 95gr Berger. I checked the internal h2o volumes of around 15 pieces of brass after the 1st fire and they were so close I just loaded and shot them from there. Necks are also turned to 10thou, I uped the load a bit and its running rite at 3180fps now with the same low ES

If lapua brass is to much work for you try some Sako brass, very easy to work with and shoots just as well

 

[rain164845]

Where can you find Sako brass?

 

[montana_native]

I reverified my jump to the lands this morning using the method described by Alex Wheeler. It turns out I am jumping the bullets almost exactly 0.100". Apparently I've eroded the throat about 0.070" since I checked it over 1000 rounds ago.

I'm going to try a seating depth test tomorrow and I'll report back. I just need this thing to get me through one more match then I am going to rebarrel.

 

[660chris1]

I have a 7.5 twist bartlien on my slr. 115's seem a little heavy for that twist rate but I could be wrong. My gun came with some lapua brass that the previous owner butchered the necks on. I get an ES of around 20 but I don't have a great scale yet. Just throwing out of a rcbs chargemaster. I also use 4831 sc

 

[LRPV]

I have a 7.5 twist bartlien on my slr. 115's seem a little heavy for that twist rate but I could be wrong. My gun came with some lapua brass that the previous owner butchered the necks on. I get an ES of around 20 but I don't have a great scale yet. Just throwing out of a rcbs chargemaster. I also use 4831 sc

You try weighing your powder on a FX120I to see if you can't get those ES numbers down...

 

[jaygorski]

I reverified my jump to the lands this morning using the method described by Alex Wheeler. It turns out I am jumping the bullets almost exactly 0.100". Apparently I've eroded the throat about 0.070" since I checked it over 1000 rounds ago.

I'm going to try a seating depth test tomorrow and I'll report back. I just need this thing to get me through one more match then I am going to rebarrel.

I run old DTACs in my creedmoor, they don't like to be jumped, running them just .002" off, and you must have a huge amount of your bottail inside the body with a .070" fb, my .173"fb is perfect for the old 115s. Whats your load for naked bullets compared to the HBN coated ones? Yea, .100" jump is a lot for old DTACs, Tubb jams his for his xc.

 

[Greg Brooks]

I actually just tried this last weekend. Started with a 56fps spread for new Lapua 243 brass - 50 pieces. Ran through steps 1-8 and the ES improved to 12fps for the remaining 50 pieces. The only change was I added steps 1-5. (Step 5 was performed BUT with just the Used Brass Die - noted below).

Hand Loads for Low ES, start with consistent brass, if your brass is not consistent pack up and go home. You are trying to create the exact same explosion/pressure every time you pull the trigger. Start with bottom of the brass and work your way up - just like building a die or race car engine.

1. File the case heads - at most 6-7 light passes on a sharp file (you will find, regardless of brand, case heads are not flat at all - do it once and you are done). You may think you are taking too much off, measure with your datum gauge. At most you might take off .008 to .010". If you fire form brass - you'll get to the same place although it might take 2-5 firings to get completely flat, depending on the pressure exuded.
   
2. Square and re-cut the primer pockets (I tend to re-cut (or clean) them every reloading maybe .0005 at most) depending on original depth and how much of the case head was taken off.
3. Tumble in corn cob or walnut
   
4. (Optional but recommended) Anneal, if you have a machine of a buddy that has one - use it, you will get a lot more consistent results. Make sure you have the dwell time set correctly, we aren't melting brass here. Like to anneal every time I have to work the brass, but make sure you let it completely cool down - or you do more damage to the cases than good.
   
5. Full Length Resize with correct bushing (try .001 to .003 tension) - I use (2) FL resize dies. (1) for new brass and (1) for used brass. If you want new brass to shoot groups, measure a large sample. Lets say we are using Norma 300 WSM brass. I will measure 200+ cases (after running through steps 1-4) to get an idea where the datum is from the factory. Pick a number you can drive nearly all the cases back to, that is what the first die is used for - the second die is utilized after you have fired for the first time and bump back .001-.003 depending on your preference.
6. Tumble
   
7. Trim to length, chamfer inside and out.
8. Tumble
9. Inspect primer pockets and flashholes
10. Weigh cases - sort to within reason
11. Prime
    
12. Drop powder under charge (RCBS or powder measure) and trickle up on a lab grade scale at minimum .02gr sensitivity.
13. Drop in 3-6" tube
14. Sort bullets base to ogive - sort to within a .001
    
15. Seat bullet - Chamber style seater w/ preferred hydraulic force press. Also used regular Redding dies and the CoAx press with great results.
    
16. Shoot and repeat from step 2

For an ongoing basis, many will just neck size, but I prefer to bump the cases back .001 each time. Whatever you want to do, not a big deal. If you want to turn necks or inside neck ream (I did either or both for many years) more power to you. I just have not seen the results on paper or the Chronograph to continue allocating the effort to turn them on the 21st century lathe while using Norma or Lapua Brass. Buddy uses same process with SAUM Remington Brass (no turn neck) and gets similar results.


This should get you to within 12-20 fps over 30-50 shots after you have ironed out the powder charge. But I would suggest running seating depth tests .030" jump down to soft jam to see if you can plow into the 5-10 fps spread. I have actually seen many strange things with seating depth from guns that will shoot with .250" jump to guys final seating bullets into the lands upon bolt close.


Turd Ferguson