Small cased .172" best primers

[MTyotehunter]

I've gotten best velocity and accuracy from my 17 ackley hornets with fed 200s

[MickMiller]

I'm using CCI450s. A slightly thicker cup, I was told, is a good idea. I'm too mean to stump up for BR4s in the UK, they're over twice the price of everything else.

[17tbs]

Thank you all very much. The federal 200 and 205 seem to actually create a smaller SD in the posted data for these hornet and smaller cases.

My intent is just to get some raw data on the e primers for velocity SD, and for actual cup thickness.

CCIBR4 seem to be well suited, yet the Federal 200, and 205 turned in a lower SD.

[GrocMax]

I was under the impression the only difference between a 450 and a BR4 is the people running the machines, and the part number.

[17tbs]

That would not surprise me Groc.

[Dean2]

Originally Posted by Tilleyman

I did some work on this topic with my 17 HH... in such a tiny high pressure case the primer does make quite a difference!

Had a couple of pierced Small Rifle primers... I know some people like to use Small Pistol primers in the 22 Hornet, but this is a relatively low pressure almost parallel sided case vs the 17 HH or 17 AH.

I wouldn't recommend using Small Pistol primers in the high pressure steep shouldered 17 HH or 17 AH...

I like the RWS 4033 primer, very accurate with N120 loads and gives a 'free' velocity boost so I bought 5,000 of them

Great post as always but for the 3 FPS difference I think I would have stuck with the CCI primers if you can get them easily. Much smaller max velocity spread and tighter SD.

[17tbs]

Does anyone know what primer Hornady uses in the 17HH?

Primer to primer ignition variance and overly energetic ignition of these small powder loads is what I am trying to avoid here, velocity is a secondary thought and a byproduct of proper and consistent ignition.

Since my barrels are shorter 18.75 inches, and 16.125" I am after a very consistent inbore pressure curve shape and muzzle exit time, I don't have the luxury of a longer barrel to provide time to evenly burn all the piwder.

This little case has some drawbacks and benefits, first it is a stonger case than the 17 Hornet, and secondly, it headspaces on the shoulder.

The problem arises because the case is small so variations in any loaded cartridge from the rest of the pack are going to produce bigger differences in boretime, pressures etc.

Hornady loads the 17HH very well, it is very consistent. It is possible that within reason the 17VHA if carefully loaded can produce the same accuracy.

I haven't gone to the lengths necessary in brass preperation for bench rest shooters, though I have neck turned, prepped primer pockets, checked neck tension and weight sorted the brass. Checking out which primers you all have been getting better, i.e. more consistent results with, is just part of what is I think a reasonable effort to maximize all the other effort I put into loading this cartridge.

Thanks for all the input, these tiny cases aren't as well suited to the ignition abilities of primers. If there were a primer specifically designed for these small cases, or if we could figure out what is used in the 17 Hornady Hornet off the shelf loads it would be great.

Over ignition can be a problem due to primers causing the powder to burn quicker than it was designed for giving a premature pressure signs and lower actual velocities.

For instance I loaded what should have been a mild H4198 charge of 9.6gr under a 17gr VMAX. Mind you I have fired compressed loads of H4198 under the 30gr Kindler Gold Boat Tail that are 9.7gr. It makes sense that the 17gr VMAX wouldn't cause pressure problems, but I am wrong, a nearly flat primer, a ruined primer pocket, and it also produced only 2884fps.

Primers probably aren't the root cause of this pressure problem but it made me seriously rethink what was going on. Since I am unsure of what really happened I am just trying to eliminate the obvious possible culprits.

I'll try the Federal 200 and see what happens. Up until now for this case I have been using up the pile of CCIBR4 & CCI450 primers I had on hand.