Have you experienced something similar with 105 a-max?

[DukeDuke]

Someone posted this on a different forum:

"I have recently broke in a new LR rifle with 32 inch PacNor,same custom 6MM Rem
night neck reamer/.272" neck). The PacNor is 1:8 and can readily push 105-107s to 3200fps.
Down side is Hornady Amax 105s come apart at that speed. The 1:9 twist did not make these Amax 105s come apart Tested at 200yds".

 

[Spotcheck_Billy]

It's been my experience that the Hornady 105 gr. A-Max bullet will come apart in flight when driven at high velocities in many barrels that have a twist rate faster than 1/9".

My latest involvement with this problem was when I tried these bullets at a hair over 3000 fps in a 28" Pac-Nor 5 groove 1/7" twist barrel that I had made up specifically for shooting the 115 DATC's. When I tried the A-Max's it quickly became apparent that at least two out of five were disintergrating in the air before reaching the target. I could actually observe the gray puffs through my scope.

It looks like Hornady is serious when they print TWIST RATE 1-9" on the end label of the box.

 

[Raptor]

My son had the same problem with the AMAXs in his 6-250. They shot great but at a match in Wyoming they were turning to gray dust. He switched to Sierra MKs and has never went back to them. I used to shoot them in my 6.5s and loved them I wish they would correct the problem with the 6mm bullets because I do like them.

 

[Turk1961]

Spotcheck Billy,

I too have a Pac-Nor 5 groove 1/7" twist barrel that I purchased to shoot DATCs with. After reading on 6mmbr about pressure problems getting the long 115s up to speed, I delayed the gun. What results did you get with the 115 DATCs and have you tried the 117s?

Dmoran,

What brand barrels did you use? Button or cut rifling? What barrel,brand, groove & twist) does your current 6Dasher have?

Raptor,

What brand, groove, twist and length barrel did your son use?

 

[brian923]

i know where talkin high power here, but i was wondering if the 105 a-max can be loaded into a 6x45,6mm/.223) and still fit into an AR mag??? thanks guys, brian

 

[Raptor]

Turk1961,
His barrel is a 26", three groove, Pac Nor super match barrel.Its very accurate with the AMAXs but just not reliable. I was kidding him about using the bullets blowing up as an excuse becuase I had shot it with the AMAXs when he was home and it shot them fine then. That fall I went over to vist him and actually seen about 4 or 5 turn to gray dust about 50 to 75yds out.

As a side note he is going to rechamber it to Roberts 243SuperX when I get the reamer. I am anxious to see how it will shoot then. I have always liked the idea of a 243 case with a 30 degree shoulder and longer neck.

 

[Turk1961]

Thanks to everyone for your info.

Anyone having problems shooting these bullets fast,3000+) out of odd grooved,3; 5; 7) 1 in 8 or 1 in 9 twist barrels? What are the problems? What type/brand of barrel?


Anyone shooting these bullets fast,3000+) out of odd grooved,3; 5; 7) 1 in 8 or 1 in 9 twist barrels without any problems? What type/brand of barrel?

 

[mbianchini]

I have never had any problems with the 105-A-Max's blowing up. I shoot them as fast as 3300 fps out of my 8 twist 243 AI.

I have crono slips pics to prove it at http://www.pbase.com/m16800/toys

 

[Turk1961]

mbianchini,

Thanks for the info and link.
Great looking gun.

How many grooves and what brand barrel?

Thanks also for taking the time to answer.

Anyone else want to help?

Richard

 

[Spotcheck_Billy]

Turk1961,
I've been shooting the 115 DTAC's naked out of my 5-groove 28" 1/7" twist Pac-Nor .243 Win. Accuracy has been excellent at 3040fps MV, but the load is too hot. I'm only getting one,and sometimes two) reloads out of Lapua brass before the primer pockets open up and won't securely hold a new primer. No other pressure signs such as hard bolt lift, piercing primers, etc., so I'm going to back off the load a bit before I continue with this rifle/cartridge. Haven't had a chance to experiment as much as I'd like due to too many irons on the fire.

I haven't tried the 117 DTAC's. I was tempted, but after hearing about some QC problems with this bullet I'll wait and see if Tubb has straightened them out before I place an order for the minimum 500 quantity. Too much $ to waste!

 

[Turk1961]

Thanks for the info, Billy. I have a 1-7 twist, 5 groove, Pac-Nor Super Match SS 243 cal blank waiting for something so I am very interested in your results. Read about others having pressure problems before getting enough speed to take advantage of the 115DTAC’s higher BC. Is the problem the 1-7 twist or odd grooves? People have had good results with Krieger 1-7.5 twist even-grooved barrels shooting the 115DTAC.

 

[Spotcheck_Billy]

Thanks for the info, Billy. I have a 1-7 twist, 5 groove, Pac-Nor Super Match SS 243 cal blank waiting for something so I am very interested in your results. Read about others having pressure problems before getting enough speed to take advantage of the 115DTAC’s higher BC. Is the problem the 1-7 twist or odd grooves? People have had good results with Krieger 1-7.5 twist even-grooved barrels shooting the 115DTAC.

I don't think that it has to do with odd vs. even grooves, but I'm not saying that it's not possible. I tend to think along the lines of Robert Whitley when he says that a 1/7 twist in a .243 bore can push pressures over a sane limit if you're already on the high side. I understand that a faster twist tends to push the pressures up, so perhaps going to a 1/7" twist instead of a 1/7.5" or 1/8" is the straw that broke the camels back with this bullet/barrel combination, at least in my case.

Tubb has been getting excellent results using 1/7.5" and 1/8" twist barrels with his DTAC's, but of course he uses the moly'd version. I might just go the moly route, but I've resisted so far 'cause I just don't like the stuff. I'm thinking that I made a mistake going with a 1/7" twist on Pac-Nor's advice when I ordered my barrel but don't get me wrong, I'm not blaming them one bit. It was my decision and my responsibility - period! I should have researched it more thoroughly before I jumped into it, but I built this rifle almost two years ago when there was much less data available on the .243 Win/DATC loads.

So far the .243 has taken a back seat to both my new 6.5x47 and another new 6.5-284 that I started playing with last spring but load development with those two is done so perhaps I'll get some additional range time with the .243 by next season.

Best of luck with your project. I wish that I had more positive information to give you about my experiences with the DTAC.

 

[rstreich]

Randy Robinette was telling about some of the testing he had done with bullets blowing up and I'm pretty sure he said that the odd-number grooved barrels were less likely to have bullets blow up--all other things being equal,or as equal as you can get them). His theory was that the opposing lands accounted for greater stress on the jacket making them more vulnerable to the stress of high-RPMs.

Don't quote me on any of this. Like I said, I think it was Randy that told me this.

 

[Spotcheck_Billy]

Donovan,

My personal experience with a 1/7" twist barrel shooting the 115 DTAC bullets leads me to "tend to think along the lines of Robert Whitley" about this subject. I've heard from others who's experiences echo mine. That's all I have! No "data or any form of facts to support this", other than what the results of the load testing that I,and a few others) have done with this combination, along with what I've gleaned from some of Roberts posts. Perhaps Robert will see this and chime in.

Sorry if you "have issues" with this.

I fully agree with your stability data, but stability is not what I'm talking about. Please don't cloud the issue. Let's stick with the question of rifiling twist/ pressure for the sake of this thread.

I normally don't answer a question with a question but I'll make an exception in this case:

What is your real world experience with the .243 Winchester cartridge loaded with the 115 gr. DTAC bullet to over 3000 fps MV in a 1/7" twist barrel? Do you own,or have you ever loaded for) this combination?

You give your suggestions about the proper twist rate for the 115 DTAC and that's fine, but then you say that you "personally use 7.75" and 8" twist barrels for the DTAC bullets" and that "my fastest is a 7.75" twist Bartlein". So am I to conclude that you've never tried the 115 DTAC bullet with a 7" twist, and that you have formed your opinions and the "issues" that appear to be attached to them strictly from your "data" and not from any actual testing?

You have a perfect right to your opinions and I certainly respect your right to post them on this thread. I expect to be accorded the same right and have expressed my opinions on the subject.

Your "issues" about "hub hub" are things that you'll have to deal with on your own.

SB

 

[Spotcheck_Billy]

Donovan,

"Keep telling everyone ......."? WTF are you trying to imply?

I was responding to a specific shooter's question on this thread when he asked about my experiences with the DTAC bullet in my 1/7" twist Pac-Nor barrel.

I'll continue to relate this information to others if they ask! Sorry if my experiences in this case don't mirror yours. Many shooters encounter different results than other shooters have encountered while using the same equipment. Sometimes it happens quite often. That's one of the things that make this hobby/sport so fascinating.

If you can't handle that all I can say is just scroll past my posts instead of becoming an internet stalker.

Your sarcasm when confronted by others experiences that do not necessarily align with yours shows that you have a closed mind in regards to anything that you haven't been able to encounter on your own. Do you claim to be the worlds foremost authority on this subject? Please tell that to all who will listen.

Especially since it's become apparent that you've never worked up a 7" twist DTAC load in your life!

I'm done with you. This s--t is getting old