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the 35/303

15 Dec 2015
@ 05:42 am (GMT)

Thomas Kitchen

Hi guys so I finally got a chance to write about the 35/303 project I have been working on.

So I better start from the start.
When I meet Nathan at reloaders supplies during the year, was when he first mentioned he was trying to convince Grant at trueflite to make a 358 caliber barrel.

Fast fordwards few months when I was emailing Nathan about my 308 norma magnum he said if I find the caliber was not to my liking put the rifle a side as he will have a 358 norma magnum reamer as trueflite was going to produce 358 barrels.

This is what got the old hampster on the wheels between my ears running about making a 35/303.
So it was off to reloaders supplies to get some speer hotcor 358 calber projectiles as they were the cheapest.
I started off with a m10 bolt that I tapered to a point to to expand the neck then using a block of wood with a hole in it to seat the projectiles,
running them through a lee enfield I found that they would load fine.

Having establish that they would work I went on to that dangerous place known as trademe rifle section.
I found a nice no4 mk1 sporter, after bit of a bid war and the appropiate paper work I had a rifle in better conditon then I thought for under $100 it even came with the dial up style aparture sights which is handy as I plan to leave this rifle unscoped at this stage.

I also needed a more reliable way of necking up the brass thankfully lee precision sell parts straight from there website, I ordered 358 winchester and 35 whelen mandrel and a 358 caliber seating plug.
I fitted the 35 whelen mandrel to a 303 full length sizing I had to expand the necks, to seat the projectiles I used the 303 seater die just winding whole die in and out to adjust seating depth at this stage.

Now came the next question how the hell was I going to get a barrel chambered in 35/303, after a lot of searching with not much help it was time to contact the guru himself.
After a couple emails with Nathan we set up a time for a phone call.
We discussed few options like using a 303 reamer then a 358 throat/neck reamer or a sperate throat and neck reamer but it wasn't an ideal situation, we also talked about using a 303 reamer then running a 35 whelen reamer in but this would end up with an improved variant of some sort which may wreck the smooth feeding.
Luckily for me one of Nathan has a client that uses lee enfields chambered in 303 epps, so he reached out to him about how smooth the feeding was.
Thankfully he got back to Nathan quickly as I wasn't havent much luck with my idea of filling a case with water clamping a bolt in the neck and heating it to expand the case. (bloody plumbers with there far fetched ideas)
it was decided that it was best to stick with standard dimensions so not to run into feeding issues and to get a custom reamer made.
Nathan also mentioned to me that the 250gr hot cors would be to hard for our local game and that the 225gr gamekings would be a far better options.

Trying to find some game kings was proving difficult thankfully the great service at reloaders supplies came through and I had gamekings in my hands in under a week,
trying the gamekings I had few feeding issues.
Thinking it may be the week spring tension in my magazine I ordered a new repo promag.
I was still having issues from one side of the staggered magazine when the bolt is worked slow if it is worked fast it seamed to be fine.
Once again I decided to contact Nathan via email, he suggested I might want to try the hornady ftx's designed for the 35 rem as they should perform like the sst's.
Back to reloaders supplies I went and thankfully they had some in stock.
The ftx feed smoothly straight away, I now had the issue that I had 3 projectiles that I wanted to shoot but needed to make sure that they would all feed smoothly.

Noticing that how I was making the dummy was putting the concentricity way off a new method was needed, Nathan had talked about the hornady neck dies in his reloading book.
A 338 and 358 hornady neck die was ordered along with a 358 ogive gauge.
In the mean time I drilled out the spare 303 seating die I had and put in the 35 seating plug from lee.

Once my ordered arrived the fun begun slowly seating projectiles checking it for feeding the checking it with the ogive gauge, after a lot of fine tuning I found and c.o.a.l to the ogive that worked well with all 3 projectiles.
I also filed a case neck open so I could check on how much each of the projectile was sitting in the neck.

Now came designing a reamer going through saami specs on things like 358win, 35 whelen and 35 rem I notices the 35 rem had a slightly tighter neck then both the 358win and 35 whelen.
Nathan had suggested a freebore of .200 thinking that using a slightly tighter neck might help prevent any accuracy issues I measured neck thickness on the ppu brass I was using and did some calculations as the last thing I needed to be doing was neck turning on a bush cartridge, running my calculations pass Nathan he confirmed I shouldn't have any issues.

Now came the time for me to design my reamer, having printed off the saami diagrams for 303brit and 35 rem I I needed to combine the two, the mainly problem was since I was leaving the shoulder angles the same as I expanded the neck the neck would become longer as it moved up the shoulder, out came the calculator and some pythagoras.
I finally was happy with my calculations so I emailed David Mansons reamers, with my designs explaining the c.o.a.l to the ogive I had worked out plus I wanted .200 freebore.
They promptly emailed me back with a design that they had transferred to their drawings.
I asked Nathan to just run an eye over it before I confirmed but it seemed to be right and got the nod from Nathan so I confirmed my order.
This is the second time I had dealt with the team at David Manson reamers and they really know good customer service which is great to see.

While I waited on the reamer I needed to find a replacement front sight as the original one would not be reuseable.
After checking a few different options I found skinner sights offer a dovetail front blade that can be filed to the right height that is designed with round edges to minimise hang ups on scrub when bush hunting.
I ordered two different heights which arrived from the states without any issues.

I now have everything sitting here ready to go im just waiting on the barrels to go into production.
The plan is to use a no5 contour sporter grade barrel 22” long with the front sight dovetailed straight into the barrel.

its been an interesting experience learning new things and i will be forever greatful that i could contact Nathan when needed, so thank you Nathan and Steph the work you guys do is greatly appreciated.

sorry for the marathon read guys but thought i would share the experience.


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03 Jun 2016
@ 05:19 am (GMT)

Nathan Foster

Re: the 35/303
Just a little something I prepared earlier...
03 Jun 2016
@ 07:49 am (GMT)

Thomas Kitchen

Re: the 35/303
thank you Grant its looking great.
i see what you mean in video about recoil, looks like a made right decision on contour.

Martin the reamer is sitting at trueflite you could order a prechambered barrel perhaps? sorry but someone has to play the devil advocate ha ha.
it should be great for a lot of the north island bush stalking we have over here.

thank you Nathan i had to laugh at your video well done.
08 Jun 2016
@ 08:29 pm (GMT)

Grant Lovelock

Re: the 35/303
Ok Thomas.... Job finished..... finally got to the range to put your 35-303 over the chrony..... shooting 200 grain FTX projectiles with 46 grains of 2206H (a full case) gave 2310fps. No pressure signs at all.
This gives you over 1800 f/lbs of energy at 100 yards and still over 1000 f/lbs of energy at 300 yards.
Shooting the open sights is a challenge for my poor old gunsmithing eyes..... but I managed a 1" 3 shot group at 50 yards..... with the low front sight it was shooting about 2" high at 50 yards so I will fit the high front sight and you will have to work out where it works best for you..... I suggest using a whited dot of tipex or similar on the blade to assertain where to file the front sight down to..... my guess is about 2-3mm higher than the low sight.

08 Jun 2016
@ 11:29 pm (GMT)

Nathan Foster

Re: the 35/303
Hi Thomas, it might pay for you to pick up a tin of 2207. See the ADI manual (.358 Win) for load notes. This will give you an extra couple of hundred feet per second if you want it.

The NNY stamped brass is quite heavy walled. But it will be easier to change to 2207 than play with Win Brass or mag primers etc. You can still make use of 2206h with heavy pills.

In any case, its good to see this job come through successfully!
08 Jun 2016
@ 11:50 pm (GMT)

Thomas Kitchen

Re: the 35/303
Thank you Nathan I had just been talking to Dan to see what powder he had in stock, was going to consult with you about with drop tube and magnum primers and what other powders to try like bm1 or bm2.
Dan manage to have win brass in stock to so got a bag of 50 303 brass to try at some stage.
Thank you to everyone for their input and help its exciting times and I'm sure my wife sick of hearing about this project ha ha
17 Jul 2016
@ 04:51 am (GMT)

Thomas Kitchen

Re: the 35/303
so the 35/303 has been home for a while and i had loaded up some ftx with 2206h to try until i have time to do a load development with 2207.

i finally got a chance to go for a hunt somewhere with the 35/303 today so i went out Thames way, well talk about horrible weather i got soaked to the skin crawling through gully's full of supple jack and rocky overgrown creeks.
it was a good test to see how handy the rifle was to carry through the crap, it looks like the stock almost had a harder time with one hunt with me then it has in the last 70 years.

anyway manage to get few shots through it just over the bonnet of the ute at 30 yards, still had the ute running as i wanted the heater to warm up.
looks good it just a shame i was aiming for top target ha ha.
i might need to find a easier target to use with open sights at a hundred to regulate the sights.
might even attach a scope for load development

and for anyone that hasn't seen the finish product its a beauty thanks again Grant
17 Jul 2016
@ 06:55 am (GMT)

Paul Leverman

Re: the 35/303
Nice rig, Thomas. You'll have fun with that one.
15 Sep 2016
@ 08:17 pm (GMT)

Ben Grady

Re: the 35/303
Hi Thomas

Have you knocked any animals over yet with the 35/303?
Those big Boars don't stand a chance.
16 Sep 2016
@ 06:48 am (GMT)

Thomas Kitchen

Re: the 35/303
i tend to use a big F off knife on the boars but the season i have had this year makes me want to give up and start collecting stamps or something hahaha.

haven't shot anything yet almost finished regulating the sight, been carrying it bit in the native.
my favourite spot has just been bombed with 1080 so i have to find a new spot for deer over the next few months.
i just had a s&k scope mount turn up for it so might chuck a scope on it sometime soon and see what it can really do
21 Oct 2016
@ 05:20 am (GMT)

Steve Richards

Re: the 35/303
I have just built a 303-35 we call it a .35 Territorian over the ditch here in Oz. I built mine using the "less preferred method " of chambering. That is a 303 reamer and a 358 neck reamer. But hey it works. I got a starting load of 40gr of 07 and a velocity of 2100fps in my 22" Sprinter barrel. Can't wait to finish off the bedding and stock work oh and to mount z nice little 1-4x20 scope.
21 Oct 2016
@ 05:42 am (GMT)

Thomas Kitchen

Re: the 35/303
hi Steve
great stuff, good to see someone else doing a 35/303.
what projectiles are you using?
im still doing bit of testing with mine i need to try 2207 in winchester brass and chrono it
21 Oct 2016
@ 08:50 am (GMT)

Steve Richards

Re: the 35/303
I'll be running 225gr GameKings for 99% of stuff here. If I do get back to the Territory again I'll opt for a Woodleigh projectile. I shot a dozen or so Buff last time up there using my 303 and 215gr Woodleigh bullets. So I trust them to get the job done. But as I said for anything other than buff or maybe Sambar deer the 225 GK's will be perfect.
21 Oct 2016
@ 10:44 am (GMT)

Steve Richards

Re: the 35/303
Here is mine thus far. Note the giant doodle on the fore end was not my doing lol. It's gone now.

22 Oct 2016
@ 12:01 am (GMT)

Steve Richards

Re: the 35/303

Maybe? Not real great with the old image insertion
22 Oct 2016
@ 06:12 am (GMT)

Thomas Kitchen

Re: the 35/303
we'll try this

looks very nice steve
whats your c.o.a.l with the game kings i was finding i had to seat them way out to feed smoothly.

i just brought a insta mount for mine, a sightron 2-10x32 would be perfect in my opinion on it also tempted to try a red dot.
im still enjoying the open sights specially when pig hunting in the tight stuff.

22 Oct 2016
@ 11:18 pm (GMT)

Warwick Marflitt

Re: the 35/303
Looks great Steve. I bet it would sort out the big Salty Crocs if you where still aloud to sink them.
24 Oct 2016
@ 06:31 pm (GMT)

Steve Richards

Re: the 35/303
COAL is 2.950" with those GameKing Projectiles Really looking forward to doing some in depth testing with a variety of loads, powders and projectiles. There isn't a whole lot of data out there for this round. So should be an interesting exercise.
08 Nov 2016
@ 02:45 am (GMT)

Bob Mavin

Re: the 35/303
Another toy for you guys.
14 Jan 2017
@ 08:33 am (GMT)

Thomas Kitchen

Re: the 35/303
just a quick update
been enjoying the 35/303 been using it when pig hunting but now its getting to hot i have fitted a s&k mount and a bushnell red dot for hunting deer in low light.
the load at the moment its 43gr of 2207 in win brass and a 200gr ftx speed is 2570 fps with no pressure signs.
will need to do full load development at some stage with a scope strapped on it, but just been enjoying using it really
28 May 2018
@ 11:31 pm (GMT)

Da Rookie

Re: the 35/303
Thomas, your results are impressive. Did you settle on the 200gr FTX? Have you tried any 250gr bullets?

I am in the process of building something similar. Action will be a No4 Mk2, parent case will be a 444 Marlin, dies will be a 35 Whelen cut shorter so the shoulder is 45mm from the bottom of the rim. I plan to use 250gr Nosler Partitions, and was wondering what speeds i can expect.

Don't know how to attach the pic of the case design from my PC.

Da Rookie
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