DRT Terminal Shock Load Data

[philcox]

Their factory loads look like your first pic. That's about how deep I have them seated in my prc loads too. Haven't had any issues but probably couldn't hurt seating them a little deeper.

I decided to go 2.700, and this is pretty close to 2nd pic. Will pressure test today. Then group on Tuesday. Will post results.

 

[philcox]

@Formidilosus
I’m trying to develop this load, but wondering a couple things, thought I’d get “Form’s take” … my setup is a stock Tikka T3X Superlite in 6.5 CM. I cut the barrel to 21.5 and put on a break. Shooting the 135 DRT, couple question:

1. what is a reasonable high end of velocity to expect with that barrel?

2. I have tried the following powders, which all seem to “perform” about the same (2850 fps and 1.6 MOA 10 shot group): Ramshot Hunter, RL16, Staball65, Varget, H4350 … of these is there one that you would “go with” or even “stay away from”? I have a lot of Hunter and RL16, and I can get my hands on 8lb jugs of each of the others.

3. I have both Peterson LRP and Lapua SRP, I have been defaulting to the Lapua, but listened to the Hornady podcast on Temp Stability, which got me wondering if I should be going LRP.

As always, you straightforward insight is appreciated, since I know no one that runs the DRT.

Thanks…

 

[philcox]

This is my version of “painful load development” (I am VERY limited of effective projectiles) so based on @Formidilosus recommendation for DRT as non-lead, I am doing my best to get a load that works at long range.

Right now my hunting load is 124 Hammer Hunter, 40.0 Varget, Lapua SRP, CCI 400, @ 2904 fps out of my 21.5” Tikka Superlite.

Total	Powder	Charge	Avg Velocity	MR	SD	Shot Count	Group	Notes on this Load
124 HH	Varget	40.0	2904	0.32	6.6	20	1.15	This load is consistently my best grouping.
130 TMK	RL16	44.0	2853	0.61	13.9	10	1.50
130 TMK	Varget	40.0	2883	0.50	2.8	10	1.52
130 TMK	Hunter	46.0	2850	0.57	13.5	10	1.69
130 TMK	H4350	45.0						Need to test Group
140 ELDM	Hunter	46.0	2797	0.44	12.1	10	1.16

My DRT data thus far

Total	Powder	Charge	Avg Velocity	MR	SD	Shot Count	Group
135 DRT	Hunter	45.5	2842	0.61	10.5	10	1.57
135 DRT	RL16	44.5	2856	0.65	6.1	10	2.57
135 DRT	H4350	44.5	2890-2900?			10	Need to test Group
135 DRT	StaBall6.5	46.5 (Flattened primer at 47, 2938 fps)	2890-2900?			10	Need to test Group
135 DRT	Varget	41.0	2890-2900?			10	Need to test Group

So I have “some” DRT data, but my load results are nowhere near what my hammers are shooting. I’ll keep at it, but wanted to update where I am. The smart man would likely just shoot the Hammers, but I seem to like to do things the hard way … more info as I progress

 

[Formidilosus]

@Formidilosus
I’m trying to develop this load, but wondering a couple things, thought I’d get “Form’s take” … my setup is a stock Tikka T3X Superlite in 6.5 CM. I cut the barrel to 21.5 and put on a break. Shooting the 135 DRT, couple question:

1. what is a reasonable high end of velocity to expect with that barrel?

2. I have tried the following powders, which all seem to “perform” about the same (2850 fps and 1.6 MOA 10 shot group): Ramshot Hunter, RL16, Staball65, Varget, H4350 … of these is there one that you would “go with” or even “stay away from”? I have a lot of Hunter and RL16, and I can get my hands on 8lb jugs of each of the others.

3. I have both Peterson LRP and Lapua SRP, I have been defaulting to the Lapua, but listened to the Hornady podcast on Temp Stability, which got me wondering if I should be going LRP.

As always, you straightforward insight is appreciated, since I know no one that runs the DRT.

Thanks…

Any of those would work. Hunter or H4350 are easy. LRP given the choice. I would 100% choose a 1.6” group with DRT than I would 1.2” group with Hammers.

 

[z987k]

called DRT, they said COAL for 135 in 6.5CM is 2.775. That means the BT is in the neck (pic 1). That OK? Should it be seated lower like the 2nd picture?
View attachment 745347


View attachment 745348

When I used the Hornady tool to find the lands, I hit the lands with the 135 DRT at 2.771, so I backed it off .020 and it's shot great. So I'm 2.751COAL with the 6.5cm and the 135 drt. 40.9gr N550, 2760fps from a 18in barrel. I could go a bit hotter but it shoots well here and takes me past where I'd want to shoot this rifle.
2.775 would be jammed into the lands in my rifle.

 

[philcox]

Any of those would work. Hunter or H4350 are easy. LRP given the choice. I would 100% choose a 1.6” group with DRT than I would 1.2” group with Hammers.

Thank you. Will see how my H4350 group does on Tuesday. Then choose between Hunter or H4350.

 

[philcox]

When I used the Hornady tool to find the lands, I hit the lands with the 135 DRT at 2.771, so I backed it off .020 and it's shot great. So I'm 2.751COAL with the 6.5cm and the 135 drt. 40.9gr N550, 2760fps from a 18in barrel. I could go a bit hotter but it shoots well here and takes me past where I'd want to shoot this rifle.
2.775 would be jammed into the lands in my rifle.

Good info. I basically looked at the projectile and put the BT at the shoulder/neck (probably in the neck in reality, but close). Was 2.700. I am going to just run with that, but since I have the Hornady tool, I may test it just to see. Thanks for the response.

 

[philcox]

Any of those would work. Hunter or H4350 are easy. LRP given the choice. I would 100% choose a 1.6” group with DRT than I would 1.2” group with Hammers.

At the risk of becoming an irritant, what is the advantage of LRP (in my case CCI 200) over SRP (CCI 400) for the 6.5CM load, and the DRT in particular? Just curious as to the "why" ... thanks.

 

[Formidilosus]

At the risk of becoming an irritant, what is the advantage of LRP (in my case CCI 200) over SRP (CCI 400) for the 6.5CM load, and the DRT in particular? Just curious as to the "why" ... thanks.

Probably nothing. But, cold weather ignition is why.

 

[philcox]

Ok, here are MY results. These are all at the range in Lincoln CA off a concrete bench. Roughly similar conditions each time I shot (although on different days). From "best" to "worst" for a 10 shot group. I usually shot all 10 fairly quickly (< a couple minutes), but tried to make sure no mirage ...

My setup again: Tikka 6.5 CM Superlite, cut barrel to 21.5", Ross Muzzle Break. 135 DRT @ 2.700 COAL

1. 1.45" group: 46.5g Staball 6.5, Lapua SRP, CCI 400, 2880 fps, 7.2 SD, 0.45 Mean Radius
2. 1.57" group: 45.5g Hunter, Peterson LRP, CCI 200, 2842 fps, 10.5 SD, .61 MR, 2.775 COAL
3. 1.69" group: 41.0g Varget, Lapua SRP, CCI 400, 2892 fps, 7.6 SD, .61 MR (this was actually only 5 shot group)
4. 2.50" group: 44.5g H4350, Peterson LRP, CCI 200, 2903 fps, 9.7 SD, .80 MR
5. 2.57" group: 44.5g RL16, Peterson LRP, CCI 200, 2856 fps, 6.1 SD, .65 MR, 2.775 COAL

So, going with the Staball 6.5. Now to group at some distance to see if consistency.

Thanks to all for your help getting here.

I have a 140 ELDM load that I will shoot when I don't have to shoot non-lead. It is money!

 

[philcox]

When I used the Hornady tool to find the lands, I hit the lands with the 135 DRT at 2.771, so I backed it off .020 and it's shot great. So I'm 2.751COAL with the 6.5cm and the 135 drt. 40.9gr N550, 2760fps from a 18in barrel. I could go a bit hotter but it shoots well here and takes me past where I'd want to shoot this rifle.
2.775 would be jammed into the lands in my rifle.

Interesting when I measured my tikka, I got a bullet length of 2.918. Boat Tail just below the tip of the neck. So based on my wanting more "metal in the neck" I am essentially a "neck length" from the lands (.218") ... seems excessive ... hmm maybe the 2.775 is what I should be running ... might have to try that. I guess I'll see how it shoots at distance.

 

[philcox]

Anyone (@SouthPaw or @Formidilosus ?) who is using the 135 DRT, what BC are you using in your Ballistic App? I was (am?) using .475, but then my Garmin Xero chrono is way off, or the BC is. I guess could be the apps, but Shooter/Revic/Hornady all pretty close. Figured I'd get some input on the BC before I start questioning my Garmin or the apps.

Thanks.

 

[SouthPaw]

Anyone (@SouthPaw or @Formidilosus ?) who is using the 135 DRT, what BC are you using in your Ballistic App? I was (am?) using .475, but then my Garmin Xero chrono is way off, or the BC is. I guess could be the apps, but Shooter/Revic/Hornady all pretty close. Figured I'd get some input on the BC before I start questioning my Garmin or the apps.

Thanks.

The manufacturer estimated .525 G1, but they had not validated it or gotten their lab results back. I took velocity data from a good amount of shots and trued the BC at 1000+ yards and it was .480ish if I recall.

Have you shot it at distance to validate data? Other inputs in your app could be off. Make sure zero is perfect. Etc.

 

[WI-Carcosa]

The manufacturer estimated .525 G1, but they had not validated it or gotten their lab results back. I took velocity data from a good amount of shots and trued the BC at 1000+ yards and it was .480ish if I recall.

Have you shot it at distance to validate data? Other inputs in your app could be off. Make sure zero is perfect. Etc.

I have not been able to true at a longer distance but your .475 BC estimate from other posts held up well at 315 yards in my 6.5x55. I will report back when I true at 500-700 but I would imagine those numbers I get would be fairly close to yours. Thanks for all the info on DRT you have shared!

 

[philcox]

The manufacturer estimated .525 G1, but they had not validated it or gotten their lab results back. I took velocity data from a good amount of shots and trued the BC at 1000+ yards and it was .480ish if I recall.

Have you shot it at distance to validate data? Other inputs in your app could be off. Make sure zero is perfect. Etc.

Will do. When you say "perfect zero", here is how I "do that". Shoot a 10 round group, then throw it into the Hornady app and get the elevation and windage offset from POA. Then adjust my turret to the closest possible. Then take the remainder and input the Elevation and Windage offsets in the app. Then, as far as I can figure, the rifle should be as "zeroed" as I can get.

So for my current DRT load, I shot

Then I adjusted the turrets "down" .2 mil (.72") and "right" .1 mil (.36"). Then I use "-.1 inch" as the Elevation Offset, and ".03 inch" as the Windage offset. I only brought 10 rounds of that load, so after the "adjust", I never fired shot 11-20 to verify that my "cone" did shift.

Then I used DRT .475 BC and 2880 FPS, and the offsets, as input into my app. I then took it to the mountains (I have 2 steel setup across a drainage, one 12x12 at 604, and a 12x20 at 936). Got up there, and wind was gusting 5-10 mph at my rifle, so I assumed similar at the target. Ended up with 16 shots there. I have a Swaro 25-50x65 spotter I use to digiscope, and for some reason, they always turn out crappy, so when a bullet does not hit the steele, hard for me to know exactly where/how I missed (take this into account when I describe my misses below)

Images should be attached in order…

Here was the sequence: Wind was L->R 5-10 mph ...
Shots 1-4 were at the 600y target. 1 & 2 missed right, 3rd seemed high. 4 SEEMED to be right on vert, and probably 4" to right

Then I went to the 936y target ... Was relevant that I am terrible at wind calling (imagine that)
5 & 6 - To the right. 7 no idea where it hit. 8 was low right.

9 Adjusted to 2935 FPS in the app and then dialed down to 6.9 (why would I change if I was hitting vertically where I was, good question) - Hit low
10 - Low right
11 - Adjusted "1 ft up", so .1 mil = 3.6", so up .3 mil? ... Could not figure out where it impacted
12 - Dialed to 7.4 after an adjust to bullet BC, keeping 2935 fps, hit low right
13 - Dialed to 7.9 hit about 1' high
14 - Dialed to 7.5, hit essentially same place as shot 5 (There an back again)
15 - Shot again, and hit low (I think)

16 - Moved back to the 600y, dialed to 3.5 (based on the new BC .425 @ 2935 fps, hit a smidge low ...

So at this point I am not sure why the velocity change between Lincoln (Lincoln CA range, 70 degrees 154 ft elevation. 2-3 mph wind) and Mountains (5000' 80deg, 5-10 wind). I did not "document" each shot.

I will go up again, with a friend that will spot impacts, as well as digiscope. Going to take my time on each shot. Make sure a solid front rest. I was using my Spartan Bipod last time. I will use an ammo can and my Molinator next time. Also making sure wind is essentially zero, to try to remove that variability in my abilites.

Any other suggestions (other than "Use the Hammer that is dialed in, and wait for your 0-600y class with @Formidilosus next summer). Is appreciated.

Thanks

 

[Formidilosus]

Will do. When you say "perfect zero", here is how I "do that". Shoot a 10 round group, then throw it into the Hornady app and get the elevation and windage offset from POA. Then adjust my turret to the closest possible. Then take the remainder and input the Elevation and Windage offsets in the app. Then, as far as I can figure, the rifle should be as "zeroed" as I can get.

So for my current DRT load, I shot

Then I adjusted the turrets "down" .2 mil (.72") and "right" .1 mil (.36"). Then I use "-.1 inch" as the Elevation Offset, and ".03 inch" as the Windage offset. I only brought 10 rounds of that load, so after the "adjust", I never fired shot 11-20 to verify that my "cone" did shift.

Then I used DRT .475 BC and 2880 FPS, and the offsets, as input into my app. I then took it to the mountains (I have 2 steel setup across a drainage, one 12x12 at 604, and a 12x20 at 936). Got up there, and wind was gusting 5-10 mph at my rifle, so I assumed similar at the target. Ended up with 16 shots there. I have a Swaro 25-50x65 spotter I use to digiscope, and for some reason, they always turn out crappy, so when a bullet does not hit the steele, hard for me to know exactly where/how I missed (take this into account when I describe my misses below)

Images should be attached in order…

Here was the sequence: Wind was L->R 5-10 mph ...
Shots 1-4 were at the 600y target. 1 & 2 missed right, 3rd seemed high. 4 SEEMED to be right on vert, and probably 4" to right

Then I went to the 936y target ... Was relevant that I am terrible at wind calling (imagine that)
5 & 6 - To the right. 7 no idea where it hit. 8 was low right.

9 Adjusted to 2935 FPS in the app and then dialed down to 6.9 (why would I change if I was hitting vertically where I was, good question) - Hit low
10 - Low right
11 - Adjusted "1 ft up", so .1 mil = 3.6", so up .3 mil? ... Could not figure out where it impacted
12 - Dialed to 7.4 after an adjust to bullet BC, keeping 2935 fps, hit low right
13 - Dialed to 7.9 hit about 1' high
14 - Dialed to 7.5, hit essentially same place as shot 5 (There an back again)
15 - Shot again, and hit low (I think)

16 - Moved back to the 600y, dialed to 3.5 (based on the new BC .425 @ 2935 fps, hit a smidge low ...

So at this point I am not sure why the velocity change between Lincoln (Lincoln CA range, 70 degrees 154 ft elevation. 2-3 mph wind) and Mountains (5000' 80deg, 5-10 wind). I did not "document" each shot.

I will go up again, with a friend that will spot impacts, as well as digiscope. Going to take my time on each shot. Make sure a solid front rest. I was using my Spartan Bipod last time. I will use an ammo can and my Molinator next time. Also making sure wind is essentially zero, to try to remove that variability in my abilites.

Any other suggestions (other than "Use the Hammer that is dialed in, and wait for your 0-600y class with @Formidilosus next summer). Is appreciated.

Thanks

You have a lot going one there.

First, find somewhere without wind or crazy elevation that you can shoot at 100 yards, and 700’ish yards without driving. Then get zero point of aim, point of impact- do not worry about putting an offset into the app. Use a simple app. Then, immediately spin and shoot at 600-700 yards and note where the group is landing. You shouldn’t go be making massive adjustments.

 

[philcox]

You have a lot going one there.

First, find somewhere without wind or crazy elevation that you can shoot at 100 yards, and 700’ish yards without driving. Then get zero point of aim, point of impact- do not worry about putting an offset into the app. Use a simple app. Then, immediately spin and shoot at 600-700 yards and note where the group is landing. You shouldn’t go be making massive adjustments.

Good advice. I have nothing like that around me that I have access to or know about. I have looked, and was super excited when I found this place. I'll see if I can figure out how to get a 100y shot in from where I am shooting, then use my 600y. It's about as good as I'll get I am afraid ... Thx for pointer (simple is better).

 

[z987k]

Interesting when I measured my tikka, I got a bullet length of 2.918. Boat Tail just below the tip of the neck. So based on my wanting more "metal in the neck" I am essentially a "neck length" from the lands (.218") ... seems excessive ... hmm maybe the 2.775 is what I should be running ... might have to try that. I guess I'll see how it shoots at distance.

I'm not shooting a tikka. My 6.5cm is my fieldcraft, but I would assume is a saami chamber since it's a factory gun.
In my 270, the DRT hits the lands a LOT shorter than any VLD bullet I've developed for as well, and the 270 is throated for a much longer bullet. But that makes sense because the ogive is so long on VLDs, it's not going to engage the lands until way further back on the bullet. The DRT bullets are a rather old bullet shape.

 

[philcox]

Went out today. Verified 100y zero, set the app to the velocity, and a .475 BC. Vertical on the steel at 600y was just about perfect. Still need a lot of practice in wind. Final load: 135 DRT, Peterson Brass, CCI 200, 46.5g StaBALL 6.5, COAL 2.715

 

[z987k]

Went out today. Verified 100y zero, set the app to the velocity, and a .475 BC. Vertical on the steel at 600y was just about perfect. Still need a lot of practice in wind. Final load: 135 DRT, Peterson Brass, CCI 200, 46.5g StaBALL 6.5, COAL 2.715

That's not much off. At 600y, that'd be .1 MOA low from published? Almost be hard to even discern that.