6XC, RE-17 and 115 DTAC

[rijndael]

Does anyone have some load data for the 6XC shooting a 115 DTAC with RE-17?

I've searched and found many references to increased velocity and load data for other 6mm chambers, but none for the XC.

Thanks.

 

[spclark]

I've pushed the DTAC115's to nearly 3200 fps out of a 30" Bartlein 5R 1:7.8 barrel late last season,latest reamer profile available back then); new Norma brass, original Russian KVB-7 & new Wolf LR primers, seated just onto the lands. Saw some pressure signs at 41 grains,of the first batch from last summer) so I'm backing off.

In 26" PacNor Rev. D reamer-chambered,late in 2007) 6XC barrel on my T2K, Saturday before last I was using 39 grains of the new batch in Tubb 6XC brass, Fed 215M's, no chrono set up. No pressure signs & better accuracy jumping them .030" than loaded into the lands.

I think 38.5 - 39.5 grains will be about right, depending on ambient temps.

 

[watercam]

While you're looking everything up I have a brand new barrel in 6XC with BN 115 DTACs:

max. with H4350 - 38gr. @ 2800

max. with Reloader 17 - 39 gr. @3000 .012" off lands

Only have 60 rounds down range so far so will see as barrel breaks in. Most people report about 39.5 gr. H4350 @ 2950-3000. German Salazar has a great article under Reloader 17/6XC.

 

[rijndael]

watercam: Thanks.

My normal H4350 load is 38.7 @ .010" off the lands,2875 fps). Much past that and I've had some pressure issues, but I knew I had a short throat and that was just fixed.

I just found that Salazar article you mentioned when I searched off www.6mmbr.com rather than inside the forum. Thanks.

 

[GermanS1]

Please bear in mind that the loads in the article were developed with Berger 115's which will show yield pressure at a given powder charge than the DTAC because the DTAC has significanty more bearing surface. Loads for the DTAC should be reduced, probably by 1.0 to 1.5 grains but I can't be positive of that amount since I haven't tested the DTAC with RL17.

 

[spclark]

Keep in mind too whether you're using Moly or Boron Nitride-coated bullets also: bare bullets require less propellant than coated for similar velocities.

I prefer Boron Nitride,whether in factory-coated bullets from David Tubb or coated-at-home) for the 6mm's I shoot now.

In all cases err on the side of caution when working up loads for your rifle under conditions you expect to shoot.

 

[rijndael]

Loads for the DTAC should be reduced, probably by 1.0 to 1.5 grains

Yea, that's no problem. I was just looking for a ballpark figure, which it provided, and I always start fairly low.

 

[rijndael]

Well, I finally made it out to the range to test out some loads. My prior load was:

H4350 38.7 grains
.010' off the lands
115 DTAC
Wolf Primer

It yielded 2875 fps,26' Rock barrel). Much past that and I had ejector swipes and somewhat heavy bolt lift.

With my RE-17 testing, from 39.0 to 41.0 grains, I had about 30 fps for every .4 grain increase.

The POI for that 2 grain spread was very close together.

The two best loads were:

RE-17 39.4 grains
.010' off the lands
115 DTAC
Wolf Primer
2940 fps
5 Shots .250 CTC

RE-17 39.8 grains
.010' off the lands
115 DTAC
Wolf Primer
2968 fps
5 Shots .375' CTC

The circle aiming point is 1' across.

I began to get some very mild pressure signs at 40.2 and 40.6 grains, specifically some ejector marks.

The velocity averages from my testing:
39.0 39.4 39.8 40.2 40.6
2899 2940 2968 2996 3035

I will head back later on to test some 20 round groups of 39.4 and 39.8 for ES and SD numbers, but so far it looks quite promising.