Home Forums Hunting & Shooting Ask The Gunwriters Rebarreling an old war horse - lots of pix, improving the cartridge

Load development can be tedious if you are working up min and max loads for 13 bullets using ten or twelve different powders. I should explain.

The ennui for me is with minimum loads, but they are important, so I have to work hard to stay focused. They are established, safe places to start.

Max loads are where 99% of shooters want to start their testing, however. Because of this, my work is concentrated there. In the case of the 30-303, I was using many bullet weights and powders for which no data existed. I had to sneak up on the max loads, and it took time. You don't just say, "I will use x grains of Hybrid V for this bullet." and shoot. I determined theoretical levels first, and built some loads, increasing them in 0.5 grain increments until I got to what I determined was the max. When you're in unknown territory, it's never tedious.



Here's a 1 inch group fired from my 30-303 using 220 gr Hornady RNs and IMR 4064
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I should say here that the majority of reloaders don't give a rat's ass about less than maximum loads. Everyone wants to ride the rocket. That's a shame. For some reason, they want to start at the book max.

Ignoring the obvious for a moment - these max loads may be over pressure for their rifle - one would hope that they wish to combine accuracy with bullet design and hit their rifle's sweet spot. It's hard to convince anyone that squeezing an extra grain into a case may only produce 20 fps more, but push pressure beyond safe levels.

But I understand why most reloaders go for the top end out of the gate.

Look at the min to max powder weights in a reloading manual for a cartridge you shoot. I'll give you an example - a 165 grain bullet for the 308 Winchester. There can be 10 grains or more of difference between their min and max loads. Most reloaders ignore most of the list, starting close to max (some at max ) looking for the magic group.

I determined years ago that the last three grains of powder was where the accuracy was. Let's say that 44 grains of Varget is the maximum powder charge for my 165 grain bullet, I start two grains below that and work up from there. For that reason, my own load data usually lists a three grain swing - 42, 43 and 44 grains. Velocities will be near the safe maximum, and the bullet will work properly. I look to the bullet maker to give me the information I need. I ensure that performance falls within their design envelope.

Great story, Years ago I had a Epps customized Enfield in 35-303 to this day I kick myself for trading it for a Modern rifle. Still looking for a semi custom MK-4 for cheap to build another 35-303.

It's definitely worth it, in my view. I imagine that it performed much the same as the 356 Win. More thump than a 35 Remington for sure. Probably closer to a 356/358 Win. You'll have to search some gun shows. Something is bound to turn up.

For all the a-holes that ask why or are so quick to opine that he should just buy this rifle or just use the 308 or the 06 . . . go screw yourselves. He did it his way 'cause it's what he wanted to do. I love it.

Thanks. I like rimmed cartridges for the most part. I also like the idea of taking something older and modernizing it. If I can use newer powders, different twists or bullet designs to make something work better, I'm all for it. It's my way of recycling!

One thing I have found on many LE's is that the barrel cannot headspace properly with a flat breech. When the barrel seats against the inner seat, the headspace is still excessive. If a longer bolt head was available,that would fix it but, failing that, I simply cut the tenon long so I could form an extension and establish the headspace when I cut the chamber. Of course, given the variation in rim thickness, a minimum chamber will still exhibit some head clearance on the brass.
My own No.4 is currently chambered for the 30/40 Krag. The case capacity is essentially the same as the 303 and the difference will favour one cartidge or the other dependent on the brand of the brass. When this rifle was still a 303, it was very accurate with most bullets and shot 30 caliber bullets very well; with some exceptions. In fact, the very best five shot group I fired with it was with 125 grain Sierra 308 bullets. This group measured right at .6" and although, I never duplicated it, I did fire many groups which were well under 1 moa. Other .308 bullets which shot very well included the 150 Speer, the 165 Speer, 200 Speer spitzer, the 150 Norma, and the 180 Norma. One bullet which absolutely would not shoot was the 180 Sierra Boattail. When I say it wouldn't shoot, I mean it really would not shoot. 100 yd groups were usually right around ten to twelve inches. The reason I shot so many 30 caliber bullets was that Dad had them on hand and the price was right. At the age of fifteen, my income was more limited than Iwould have liked and I had to stretch that reloading dollar. I did buy some CIL 180 CPE bullets which worked quite well for me and which I used the take my first big game animal (a doe antelope). Later, I got some 180 Sierra .311 bullets and these weremy preferred bullet for that rifle for as long as it was a 303.
As a 30/40, it has the advantage of being a 30 caliber with the abundance of bullets that provides. The barrel is a twelve twist MRC, stainless and it works well with everything from 125's to 220's.
I load the 30/40 a bit stiffer than I would for a Krag but not a lot. I have found that loads which duplicate a 300 Savage are great and give long case life while loads which approach 308 levels will reduce case life quite a bit. Workable maximums are like this:
125's... 2800fps
150's... 2700fps
165's... 2600fps
180's... 2500fps
220's... 2275fps.
For the most part, these loads give reasonable case life (a half dozen loads) and are adequate for any game I want to shoot. Reduce them a hundred feet and case life is easily triple and field performance is still fine.
When I was a kid, I always thought a 375/303 would be a great cartridge but I think a 35 would be better. The ability to use 357 pistol bullets for small game loads is a real plus, I think.
Steve, the cera-cote looks great; quite a bit better than the Tremclad I dobbed onto my stainless barrel. GD

I decided on the Cerakoting because I had seen it before at a trade show and liked the resistance to the elements. There are many formulations, but this one was inexpensive and readily available. I like its appearance.