Accuracy nodes for 115 DTACs

[Jaxdialation]

I'm working up loads for my 243AI. At this point I'm fire forming very accurate loads using H4350 + DTAC.

I anticipate that around 2980 - 3005 will be an accurate node based upon my testing so far during fire forming out of a 7.5 twist barrel.

<span style="font-weight: bold">I'm not looking for "loads"</span> I'm interested in velocity/accuracy nodes. Are there any above that 3000fps range? I have plenty of room to push the bullet faster, but how far do I have to go to hit another node? Any caliber using these DTAC 115s would help.

Thanks in Advance!

 

[725franky]

Re: Accuracy nodes for 115 DTACs

I'm still learning myself, so I may not be completely correct; however, I was under the impression that accuracy nodes were specific to each gun, mostly based on the bbl length.

Maybe I'm missing out on an shortcut... if all projectiles only need to reach a specific speed, finding a load would be a direct science rather than somewhat of an art form.

Okay, I guess my understanding of the nodes is that they are somewhat similar to a 1/4 mile drag time; you can hit the quarter mark at a higher mile per hour but still loose the race to a guy who's car accelerated more quickly, while finishing at a lower mile per hour.
How this relates here is the node is more the timing of the bullet exit (from the barrel) rather than the speed that it leaves the barrel. Different powders = different rates of acceleration.

- Frank

 

[Jaxdialation]

Re: Accuracy nodes for 115 DTACs

I think you would be surprised how useful the answer to my question is. The variable you mention are interesting, but just aren't that significant in this case, because 115 dtacs dictate
twist rates and barrel lengths.

 

[Rob01]

Re: Accuracy nodes for 115 DTACs

Mine shot great at 2980-2990fps. When it went above 3020 it opened up. When I went from moly to Bn I had to drop my charge of H4350 down .3grns as it jumped my velocity to 3030fps and groups opened. Got it back down to 2990fps and tightened right back up.

 

[00bullitt]

Re: Accuracy nodes for 115 DTACs

2960-2990fps gives me 3/8MOA accuracy at 100-400 yards but the groups were not holding so well at 600+. They opened up to almost 1MOA. I increased the charge a little for 3060fps and lost some accuracy at shorter range(now 1/2MOA) but maintained it further. My barrel is a 1/7.7 twist Bartlein. I use the hBN coated DTACS with 49.4 grains H1000.

 

[DocB]

Re: Accuracy nodes for 115 DTACs

j,

Try something around 3150 f/s. You don't state a barrel length and that's kind of important.... Don't try it with the 4350's. 10+ years of .243

HTH,
DocB

 

[jwp6114]

Re: Accuracy nodes for 115 DTACs

educate me if im wrong, but doesnt contour come into affect too? If we are tuning the bullet to exit the barrel at a certain point in vibration i would assume heaver contours would be more forgiving? (I.E. less whippy)

 

[Jaxdialation]

Re: Accuracy nodes for 115 DTACs

All sorts of stuff of variables are involved in accuracy guys.

So far I'm seeing my best results at 500 yards in the 3040fps area. I'm shooting fire forming loads for my 243AI.

I'm just not hearing about real people driving these bullets much above 3050. Even Tubb says his optimum velocity was 2988 to 3020 fps. Lot's of people quote George Gardner's load, but I'm getting skeptical that there are good loads to be had at 3150+ fps. I certainly will have the ability, to launch these bullets at those velocities. No problem there.

Oh notice how the velocity change among the last 3 loads is negligible. Those were .1 gr increments. H4350 is great up to these velocities (up to 3050).

 

[jwp6114]

Re: Accuracy nodes for 115 DTACs

Wish that chart showed your powder charge, I too am using IMR4350, but I am no shooting the Dtac's, rather the 105 a-max (sorry for being off subject with the a-max)(i dont think the dtac will stabalize in my twist). If I can find the pic I will post it up, I did load development at 400 and ended up with a near 1" group.

My rig:
Rem 700
Factory 1&1/8 twist varmint 26" barrel punched to an AI chamber
True'd action
Vais break
Schillen trigger
B&C tactical medalist stock glass bed'd
20 MOA NF base
NF 5.5-22x56 HS/ZS (in an ARMS QD mount)

My load
Win brass
Fed 210m primer
42.5gn of IMR 4350 (avg velocity 3020)
105 A-max seated to 2.862
(IM NOT EXACTALY SURE HOW FAR IM JUMPING THEM)
I need help obtaining a modified case in 243AI
or i need to borrow or purchase a 7/16 - 36 tap
to make my own (HELP) usint the ram one in there method...



3 @ 400yds

5 @ 1000 1MAO bull (looks close to .5MOA tall group im no pro at wind)

my rig

 

[jwp6114]

Re: Accuracy nodes for 115 DTACs

I also can tell you this (im sure most people dont shoot factory remington barrels) but @80 rounds theres so mcuh fouling rather it be copper or carbon that the accuracy falls on its face... I have been doing detail'd cleanings every 50 (removing carbon and copper), need to try removing just carbon after 50 and see how it does for another 50 to see if its the coper destroyinh the accuracy.
im sure a premium barrel (smoother inside) would help. ive seen the inside of this one

Stay away from a bore scope... it scared me. I shoot mine like a .308 and have experianced about .030 or erosion/corrosion (whatever you want to call it) in 480 rounds... eeewwww. but i have friends donating me factory barrels at this point.

also would like to know if anyone has done any tests on velocity changes with ammo/powder temp, dont know if its just the atmospheric conditions but my gun shoots about 25.5 MOA to a grand at 95*f and about 27.5 at 75*f

 

[DocB]

Re: Accuracy nodes for 115 DTACs

JWP,

Somewhat simplified: Length determines the node (4th, 5th, etc.), contour determines how steady the amplitude at the node will be.

HTH,
DocB

 

[jwp6114]

Re: Accuracy nodes for 115 DTACs

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocB</div><div class="ubbcode-body">JWP,

Somewhat simplified: Length determines the node (4th, 5th, etc.), contour determines how steady the amplitude at the node will be.

HTH,
DocB</div></div>

a little over my head for a GA public education like mine...
i will read up on it and try to make sence of that though... (looking up defintion of Node now)
Got it... now i understand...
I am learning so much so fast its crazy from hand loading to cleaning theres so much to learn...

now if some one could help me with osmosis of wind and marige knowledge

 

[DTubb]

Re: Accuracy nodes for 115 DTACs

Henry Childs successfully uses 115 DTAC's in his modified 270 case at 3268 fps in 600 yard BR matches. Henry is very knowledgeable with any subject dealing with long range accuracy.

 

[Trovan]

Re: Accuracy nodes for 115 DTACs

If you have Quickload, use it with the Optimal barrel time charts found here:

http://www.the-long-family.com/optimal%20barrel%20time.htm

Read the background on the site and look at the pdf paper with the nodes listed.

I have found this to be very useful in finding loads quickly You can adjust your barrel time by adjusting the load variables. Quickload will then give you the speed at that node. It isn't perfect but it gets me a very close starting point.

 

[jwp6114]

Re: Accuracy nodes for 115 DTACs

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Trovan</div><div class="ubbcode-body">If you have Quickload, use it with the Optimal barrel time charts found here:

http://www.the-long-family.com/optimal%20barrel%20time.htm

Read the background on the site and look at the pdf paper with the nodes listed.

I have found this to be very useful in finding loads quickly You can adjust your barrel time by adjusting the load variables. Quickload will then give you the speed at that node. It isn't perfect but it gets me a very close starting point.

</div></div>

my head is about to reach critical mass

shut up brain or i'll stab you with a q-tip"

 

[Jaxdialation]

Re: Accuracy nodes for 115 DTACs

Thanks David.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DTubb</div><div class="ubbcode-body">Henry Childs successfully uses 115 DTAC's in his modified 270 case at 3268 fps in 600 yard BR matches. Henry is very knowledgeable with any subject dealing with long range accuracy.
</div></div>


Good stuff Trovan. Thanks.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Trovan</div><div class="ubbcode-body">If you have Quickload, use it with the Optimal barrel time charts found here:

http://www.the-long-family.com/optimal%20barrel%20time.htm

Read the background on the site and look at the pdf paper with the nodes listed.

I have found this to be very useful in finding loads quickly You can adjust your barrel time by adjusting the load variables. Quickload will then give you the speed at that node. It isn't perfect but it gets me a very close starting point.</div></div>

 

[MTETM]

Re: Accuracy nodes for 115 DTACs

-<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">Mine shot great at 2980-2990fps. When it went above 3020 it opened up. When I went from moly to Bn I had to drop my charge of H4350 down .3grns as it jumped my velocity to 3030fps and groups opened. Got it back down to 2990fps and tightened right back up.</div></div>

This is my experience as well...2980-3000

I know of an accomplished shooter who runs them at 3150 and has found a very good node in his rifle...

 

[RobertB]

Re: Accuracy nodes for 115 DTACs

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DTubb</div><div class="ubbcode-body">Henry Childs successfully uses 115 DTAC's in his modified 270 case at 3268 fps in 600 yard BR matches. Henry is very knowledgeable with any subject dealing with long range accuracy.

</div></div>He shoots at our benchrest matches and he is very interesting to talk to. His rifle is a work of art to say the least. He is a local guy that I'm proud to be able to learn from.

 

[RobertB]

Re: Accuracy nodes for 115 DTACs

BTW, I think of the "node" in reference to the bbl. I shoot 142 SMK in 4 rifles all of them have their "nodes" at different speeds. When I launch them from my 6.5x47L 22" I can go up to a certain speed till the groups start to really open up, but then when I send em from my 6.5x284 Shehane with 32" bbl they are shooting just as tight as the other calibers at much faster speeds. People ask me about the heavy rifles and think its good to "test loads" from. I always tell em I believe that you can only test loads for a rifle out of that rifle. Thats just my way of thinking and I am far from the brightest guy in the world.