DRT Terminal Shock Load Data

[Trackselk]

I'm getting a 223 barrel or 2 throated long for the 79 DRT bullets. Anyone have any idea how long beyond my CBTO I should go, or how much minimum jump I should ask for? I'm other words; do these things like to jump like monos, or jam? I generally load pretty hot so I don't jam bullets, but I might if it was the only setup that worked. Thanks for any advice!

 

[cubdriver84d]

I'm getting a 223 barrel or 2 throated long for the 79 DRT bullets. Anyone have any idea how long beyond my CBTO I should go, or how much minimum jump I should ask for? I'm other words; do these things like to jump like monos, or jam? I generally load pretty hot so I don't jam bullets, but I might if it was the only setup that worked. Thanks for any advice!

I would aim for 0.020 jump with top of the boat tail right at the bottom of the neck. Similar to the photo in post #45 https://rokslide.com/forums/threads/drt-terminal-shock-load-data.347403/post-3733960.

I haven't done any seating depth testing but haven't really felt the need to either. I just load to 0.020 or mag length and shoot.

 

[Trackselk]

I would aim for 0.020 jump with top of the boat tail right at the bottom of the neck. Similar to the photo in post #45 https://rokslide.com/forums/threads/drt-terminal-shock-load-data.347403/post-3733960.

I haven't done any seating depth testing but haven't really felt the need to either. I just load to 0.020 or mag length and shoot.

Thanks! Now to find a smith with a 'close-enough' reamer

 

[philcox]

I think 555 and 560 will be too slow. I'm going to play with the 135 in 6.5cm here soon. 550 and rl17 will be what I start with.
Stable will probably be good. For those 3 powders I'd start there.

You ever get a load you like with the 135?


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[philcox]

Anyone ever ask DRT what powder they recommend for the 135 and 65CM?

I bought a 20 Factory load to see how they shoot compared to my hand loads. I weighed all 20, about a 4g delta between all of them, so I know they all have powder

Also, I measured them, and basically 2.760 it seemed, so that is what I will use going forward. I’m gonna call and ask about the powder. I’ll reply with what I find.


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[philcox]

My results from yesterday. I have yet to get any load that is anywhere near the accuracy of my 124 Hammer Hunters. Interesting thing is that I can't seem to get LRX or the DRT to shoot well. I have tired in 2 separate Tikka 6.5 CM. I am starting to wonder if it is the shooter and not the load. ...

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[Geysermutt]

I posted on the other DTR thread but figured it would be better here.
Tikka t3x 6.5cm 24” barrel
Lapua LRP brass sized down .002 headspace
Remington 9 1/2 LRP primers
135g DRT
Seating depth- coal 2.6800 or cbto 2.2475
44.5g Staball 6.5 (.5g under max)
Shots a 10 shot group right at 1”
Unknown velocity at this point

I’m trying out h4350 as well to see if I could use a more temp stable powder. Even with staball 6.5, the mv at different temps should have negligible poi differences under 500yards.

Edit: with the 44.5 grains of Staball 6.5 I crono’d the velocity and I was getting 2922fps. Probably a bit hot since book max is 2870, so I’ll drop another .5 grains which gets me to 2891fps

 

[WI-Carcosa]

Another successful DRT 6.5 Swede combo. 45.5 g of n555. Thus far the DRT bullets have shot well in 223, 6.5x55 and 300 wsm for me. Will be trying the 135s in a 6.5 PRC this summer as well.

 

[philcox]

@Formidilosus any input on where to start RL16 (43g?) on the 135 with Hornady brass? I also have G210M, CCI 200, or CCI 250 I can use for primers ...

 

[z987k]

@Formidilosus any input on where to start RL16 (43g?) on the 135 with Hornady brass? I also have G210M, CCI 200, or CCI 250 I can use for primers ...

Start at 43, work up. Max is likely up around 45.3

 

[Formidilosus]

@Formidilosus any input on where to start RL16 (43g?) on the 135 with Hornady brass? I also have G210M, CCI 200, or CCI 250 I can use for primers ...

I would start at 41gr RL16 and Fed 210m.

 

[philcox]

Start at 43, work up. Max is likely up around 45.3

What are you looking at for COAL? I've seen everything from 2.775 to 2.700 ...

 

[z987k]

What are you looking at for COAL? I've seen everything from 2.775 to 2.700 ...

2.771 is where I hit the lands with the 135gr. I'd measure yours before loading anything.

 

[philcox]

Using the Hornady OAL guage, I am getting a range of 2.875-2.900 as the OAL with bullet touching lands. Not sure why I am getting the 0.025 variance. Likely my accuracy with my tools. I may just load to the DRT factory 135 6.5 length.


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[philcox]

Trying to consolidate the data from this post here https://docs.google.com/spreadsheets/d/191nr3Zhfv1KWQXzneblq2Y1KOj709OGSRLSzFUM3jFc/edit?gid=0#gid=0

Any updates or clarifications are appreciated.

 

[Geysermutt]

Trying to consolidate the data from this post here https://docs.google.com/spreadsheets/d/191nr3Zhfv1KWQXzneblq2Y1KOj709OGSRLSzFUM3jFc/edit?gid=0#gid=0

Any updates or clarifications are appreciated.

You can add velocity as well. I’d caution anyone using those loads without working up to them when reloading. I edited my post a few weeks ago to show velocity I actually got. The load charge was well under book max but the measured velocity was over the estimated velocity. I lowered my charge to bring it down to a safer velocity (pressure)

 

[philcox]

Tired 22.0 and 22.5 XBR @ 2.240 with the 79g. I do think the POI shift on the 22.0 was more a positional change, and not as much load driven (where as the 22.5 is definitely load), so going with that as my final load 79 DRT 22.0 XBR @ 2.240 CCI 450 1x Starline Brass.





Going to load up another 100, zero with 30, then velocity true at distance.

Now to find the 135 load, and be done with this ...

 

[philcox]

Final loads I ended up with ... I'll go with them and limit my distance to the "limiting item" of skill or group size.

223: 79 DRT, CBTO 1.828 (~OAL 2.24), 22g IMR 8208 XBR, Starline brass, CCI 450. ~2521 fps
65 CM: 135 DRT, CBTO 2.30 (~OAL 2.775), 43g RL16, Peterson LRP, GM210M. ~2751 fps

Will do a 30 round zero to get the cone of fire for both, then distance true velocity. Ideally will get 1000y for the 65 true, and 700y for the 223.

 

[WI-Carcosa]

Final loads I ended up with ... I'll go with them and limit my distance to the "limiting item" of skill or group size.

223: 79 DRT, CBTO 1.828 (~OAL 2.24), 22g IMR 8208 XBR, Starline brass, CCI 450. ~2521 fps
65 CM: 135 DRT, CBTO 2.30 (~OAL 2.775), 43g RL16, Peterson LRP, GM210M. ~2751 fps

Will do a 30 round zero to get the cone of fire for both, then distance true velocity. Ideally will get 1000y for the 65 true, and 700y for the 223.

What’s your 223 barrel length? My suppressed 16.5” T3x does 2510 fps avg with the factory DRT 79s and 10 round groups under 1.4 consistently closer to 1moa when I am not really sucking. They are out of stock now but I have been pleased thus far shooting about 200 rounds of the elite and elite seconds from the factory.

 

[philcox]

What’s your 223 barrel length? My suppressed 16.5” T3x does 2510 fps avg with the factory DRT 79s and 10 round groups under 1.4 consistently closer to 1moa when I am not really sucking. They are out of stock now but I have been pleased thus far shooting about 200 rounds of the elite and elite seconds from the factory.

223 is 18", and the 65 is 21". I am not suppressed, as I live in a state ran by seriously evil people. I was 2530 (1200' alt, mid 70's for temp when I shot the Factory) and 1.75 MOA. It is likely a decent load, but I am not a very smart guy, and always think I can load better. Also, have heard some horror stories on some DRT factory loads. I don't care when shooting, but if a hunt shot is on the line, I want to know who to blame if the firestick does not go "bang".

My 79 DRT cost me right at $1.15/round. Factory is about $1.60 (but I don't have to spend time)