Wildcat load data help needed

[hounddawg]

looking for some load data on a new wildcat cartridge which is a 6.5 Grendel case necked up to .30 cal. The smith is going to contact the previous owner of the rifle to see what he used but considering the current powder situation I am not sure if I can duplicate it. If the previous owner used 4198 I am screwed, that stuff is rare as hens teeth at the moment

the bullet I will be using is the 115 Berger flat base

3 powders I have on hand that may work is 8208 XBR, CFE 223, and Tac. I am figuring that if I take the starting load for a normal 6.5 Grendel with a .264 diameter 115 gn bullet and reduce it 10% to 15% to account for the larger bearing surface of the .308 diameter bullet I should be in safe territory

Thoughts or Quickload data anyone ? Or suggestions for other powders that can be found ?

[44 AMP]

a new wildcat cartridge which is a 6.5 Grendel case necked up to .30 cal.

Looking at the specs, the new wildcat essentially duplicates the 7.62x39 Russian. it's the same length, the Grendel case is 0.005" smaller at the head.

Wiki say both cases are approx 35gr H20 capacity, 6.5 Grendel is a 55,000 psi round, 7.62x39 is a 45,000 psi round.

That should give you some idea where to start.

[lordmorgul]

Quick load has 6.5 Grendel as 37.5gr nominal volume at 58k psi max and 7.62x39 Russian as 35.5gr volume at 51k psi max. Opening the mouth should just barely bump up the volume?

QL seems to show, 16” barrel, 2.2” COAL, assuming 7.62x39 case at 35.5gr volume, Berger 115gr FB, using the 7.62x39 max pressure 51k

with CFE223 you could fill the case full (36.8gr) compressed and be 51k psi, 2417fps.

with TAC it would over pressure if full, 34.5gr gets to 51k at 2410fps

With 8208XBR 33gr 50k psi at 2460fps

So I’d prefer working with 8208XBR of the three for best result and some headroom but actually CFE223 seems very forgiving to develop since it’s hard to overdo it, and starting low.

If assuming a 6.5G case, and force a similar bullet length of 0.94” as your Berger 115gr .308, and force a weight of 115gr, the pressures are higher and you would have to seat longer and reduce the powder by about 1.5gr.

so somewhere in between is the truth.

IMR4895 would give a slightly higher velocity (2500fps) for same max pressure at ~34.3gr assuming above 7.62 case

Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!

[hounddawg]

Thanks for the input guys. Looks like I finally have a good excuse to buy my own copy of Quickload. At the moment though just setting the gun with a scope and all the components for a new cartridge is eating up cash fast

the rifle is being sold with 2 barrels a 6 PPC and this 30 wildcat. I am going to give in 100 and 200 yard group shooting a try so the PPC barrel will be getting the most rounds at first at least. Down the road I may try the 30BW for score shooting or even give it a try at 300 yard F class

[hounddawg]

talked to the smith this morning , he said reducing the minimum 6.5 Grendel load by 15% so would probably be a safe start for development but agreed that a Quickload purchase would be the best bet. I am going to mess that barrel later on this winter when things calm down a bit. Right now my main concern is getting my new reloading room set up

[44 AMP]

Quick load has 6.5 Grendel as 37.5gr nominal volume at 58k psi max and 7.62x39 Russian as 35.5gr volume at 51k psi max.

These numbers are different from what is listed in Wikipedia. I make no claim for the accuracy of either, but consider this, first they are different, and neither can take into account the actual volume of the brass you have (or will have..)

This is the "flaw" in computer models, unless you can input the precise data you have for YOUR components and firearm (if you even have them) then the computer program assumes certain values and calculates, based on them.

The results will have some relationship to what you actually have, but its unlikely for them be be exactly what you will get.

[jetinteriorguy]

I’d look at RE7 or Accurate 1680. 1680 literally made for 7.62x39. Ive used both with good results, with the nod going to 1680.

[Unclenick]

HD,

You can also download Gordon's Reloading Tool free. It is starting to have more U.S. powder models in it.

[hounddawg]

This is the "flaw" in computer models, unless you can input the precise data you have for YOUR components and firearm (if you even have them) then the computer program assumes certain values and calculates, based on them.

or in old school terms, garbage in = garbage out

thanks for the suggestions jet. I have never played with the 7.62 x 39 but it does look like the case volume is about the same, both .30 cal etc. The smith has been using this wildcat for a lot of years but in a different twist and a lighter bullet. This barrel has a lower twist optimized for 110 to 115 gn bullets and the original purchaser only put 30 rounds down the barrel. I will have some fun with it and plan on trying several powders hoping I can get 30 BR performance grouping wise. If not I still have a low round count 6 PPC for a great price which is really what I wanted in a rifle anyway

[lordmorgul]

Originally Posted by Unclenick

HD,

You can also download Gordon's Reloading Tool free. It is starting to have more U.S. powder models in it.

I did the same checks I have above in QL with GRT and pretty similar results. I’ve never it all my own loads into both tools where powder is available and in my opinion GRT is very good. Results vary of course, different models and different inputs, but both are very valuable tools.

And Yes AMP it is absolutely necessary to measure your own case volume and bullet length and seating depth to get the models to align with measured velocities consistently. But it can line up very closely with work. The above is notional only for best powder selection.

Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!

[stagpanther]

I agree you're probably very close to 7.62 x 39 in characteristics, in which case I'd be looking at 1680, shooter's world BO and CFE BLK.

[hounddawg]

I have been doing some research on the cartridge and finding some very interesting facts on it. Turns out it has been around for a number of years with different names. it has been around since at least 2007 and called the 30 Gremlin, 30 BW, 30 Walker and 30 AS, 30 Ergle, 30 Major, 30 Grendel,30 PPC, and 30 ARX. The 30 ARX was briefly marketed by Robert Whitley as a alternative to the 300 blackout for AR platforms. In 2013 Mike Stinnett nailed a .0077″ group in competition using a necked up Grendel and Bibb 114 gn bullets with 4198. He called it a 30 Stewart.

Just as a few of you guys suggested 4198, rl7, 1680, n120, 5744, norma 200 powders have been suggested. I have none of those on hand but do have a good supply of H322 and BLC 2 which have been used in 7.63 x 39. 1680 and N120 can be found on the net and I am thinking of doing a tour of LGS's Wednesday to see what I can scrounge off the shelf locally.

I am speculating this barrel will have one heck of a life since a 30 BR uses more powder and gets over 5K rounds in competition. I doubt seriously now if I will ever use the 6PPC barrel except for practice

[reynolds357]

In my mind, 300 Blackout max would be good starting load.

[jetinteriorguy]

About 30 years ago I used a lot of Blc2 in my 7.62x39 with very good results. Almost as good as 1680.