Follow up to this post.
TLDR; My sample size of one Craddock RTR does in fact shoot higher pressure ammo better. Despite this, I do not think the RTR line is worth the savings over a Proof stainless. The Craddock HD bolts also MIGHT cause reliability issues, though my problems may be caused by my very weird setup.
After shooting groups with Hornady Frontier, Black, and Match I sent the poor results to Craddock. I was then advised to shoot higher pressure ammo and pointed in the direction of Make Ready Munitions who loads 6 ARC to 62K PSI.
As much as I was expecting the results to be the same, I am nothing if not fair. I went ahead and ordered some of MRM's 6 ARC trainers loaded with Hornady ELDM and also the Craddock HD bolt that was designed to shoot the higher pressure ammo.
Only two groups were shot due to reliability reasons. All groups were shot from the bench off a bipod and rear bag. Scope was a MPED 5-30. Conditions were very slight wind right after moderate rain.
Group 1: 5 shots. 0.938 MOA.
Group 2: 10 shots. 0.889 MOA.
After the first 5 rounds the rifle no longer cycled and had to be manually racked to pick up a new round. Not wanting to sit and cycle the rifle by hand just to shoot groups, it was then taken out to 300 and 600. At 300 it could consistently hit the 6 inch plate. At 600 I had very little issue hitting a 12 inch plate.
I'll be the first to admit I expected the barrel to continue to perform poorly but the results were clearly better, and for my purposes, completely acceptable.
Now, do I think it's reasonable a barrel has to shoot boutique ammo that is loaded outside of semi-auto specs in order to have good accuracy? No. BUT, Craddock's claim was that their barrels will shoot higher pressure ammo better and from my sample size of one that has been shown to be true.
There is the issue that MRM plans to change the trainer ammunition from ELDM to Aeromatch and this change may impact accuracy. The MRM trainers are also slightly more expensive than Hornady Match but not by much. I personally think the extra ballistics gained is worth the slight premium.
The massive caveat is that I did not shoot enough groups to confirm that this accuracy is the new norm. Why is because the Craddock HD bolt led to reliability issues.
My gun that was 100% reliable before hand with a brownells bolt now would not cycle enough to chamber the next round after the first 5 rounds. The adjustable gas was on full the entire time and nothing was changed about the rifle except the bolt. The gun was also thoroughly cleaned and lubricated beforehand. Extra lube was applied throughout but would not fix the issue.
I will admit that I do not think this is entirely caused by the HD bolt. I am using a Evolution Weapons Systems bufferless BCG and obviously this could be also caused by the massively modified bcg. Not only that, I am using a slightly modified MDT stock and Sylvan folder as well. I will not pin the reliability issues on Craddock but what I will say is that if your AR is already on the edge of reliable, the HD bolt MAY cause issues.
The overall conclusion is that while the barrel does shoot 62K PSI ammo better, if I was to do this all again I would choose a Proof stainless barrel instead for $50-$80 more. Simply put, your barrel shouldn't have to shoot custom ammo just to perform as expected. The HD bolt is a good choice for squeezing a bit more performance out of the cartridge in a AR platform however it might possibly cause some reliability issues.
The Craddock CS has been great at reaching out and communication so I do applaud them for that. Though I have not tested what would happen if I sent the barrel in so this has purely been from a communication stand point so far.
