Building New Rifles: 7mm08 & 223SHORT

[Arth]

Everyone does that once I think

[Gwion]

Well. The rings where on the wrong way, not the scope. With a 56mm objective lens, it's pretty obvious which way it goes.

[Tonit]

Well. The rings where on the wrong way, not the scope. With a 56mm objective lens, it's pretty obvious which way it goes.

I think that would be grounds for giving up your license if you couldn't work out which end of the scope to look through

[Gwion]

I've started inletting the stock for the Zastava. It is a right hand stock that i am converting to a fully ambidextrous stock. It's roughed out with a chisel and i'll get the dremmel type tool onto it tomorrow, then bed it, then finish it with a home made concoction of bee's wax and linseed oil. AS time allows i'll post some pics of the progress.

Also informed by my gunsmith that the 223MacShort reamer has arrived. Now i need to chase up the reloading dies and get it chambered to suit. Funds allowing, it will all be ready to go in a month or so.

Now that i'm back from out little holiday and the schedule is somewhat more open, i can start load development for the 7mm-08 as well.

[Gwion]

So. I wasted a whole lot of perfectly good bullets doing a full scale load test, from min to max in 0.3 increments.

7mm Hornady 162 A-max don't come cheap!

There was a nice load early on. It shot 0.5 & 0.4 inches (two groups of 3 shots) at 100m. Probably should have stuck with that but just had to go through the whole range, looking for a mid way charge and a top end charge. As i'll be shooting out to 600yd for some club F-class, i wanted to push the velocity as far as i could and still have a pretty good load. I took it to 0.2gn over book max with barely a sign of pressure, so might keep looking for a hotter, tighter load.

Well, 45.4gn of AR2209 loaded to the lands gave me a couple of three shot groups of >0.5<0.6" @ 100m. Playing with 10though jump & 10thou jam opened it up to about 0.75", so i just went loaded to the lands.

Off i toddle to the range with 5 loaded at 45.3 & 5 @ 45.5 with the remainder at 45.4. I do this just to see if either side will give any improvement.

I was already zeroed at 100m, so 3 sighters had me in the bull at 300yards, using the 45.4 with 2MOA adjustment for elevation. Wind was almost non existent so windage dial stayed on ZERO.

For the first shoot with this new rifle (barrel and cartridge change), new load and new scope, i was quite happy with a couple of 50 scores (50.3 and 50.1).

First string, first sighter... bang in the X, second sighter, 6. Don't know what happend from there but my shooting position wasn't real comfy and i couldn't shoulder the rifle as i would normally and was getting caned by the butt plate. I'll go back to using my usual rear rest next time.

Second string was nice and consistent for grouping but was dropping low and left into the 5. With small adjustments to the scope after each shot i ended up managing a couple of 6 and another X but also 2 fliers kept my score down to 50. While loading, i did notice quite some variation on neck tension. The recent holiday ate up my funds for neck turner, etc, so all those fine tuning toys will have to wait!

All in all i was pretty happy with the first outing but not so happy that i am now out of bullets (still have 120 hollow points to develop as well). Hopefully i can get some more A-max before next shoot and get more comfortable and confident with the rifle. Next shoot is 500yd.


Update on the 223McShort. The reamer arrived but with no Go guage, so no go to build it yet. Also, still waiting on dies to form and load the cases... bit annoyed with the service on that but not sure if i should just cancel and start again with another supplier. The rifle is now chambered in 223rem and i am waiting on delivery of some good bedding compound to do the final fit and finish on the stock. It has had pillars fitted and is all stopped up and taped, ready for the job when the goo arrives in the post. The Zastava action was pretty rough to cycle, but careful file work on the bolt rails then some lapping compound and 1/2 hr working it while watching TV has smoothed it right out. Really looking forward to getting it shooting and quite frustrated with all the delays in items being delivered!

Anyhoo... that's where it's all at as of today.

Cheers.

[Gwion]

In the process of bedding the 223. Hopefully I haven't stuck it all together and I can start final finish tomorrow.

[Chronos]

Sounds like you're all over it G

In my Tikka 46gr o '09 at 200Y saw the 162 AMax group under 1/2moa seated at 2.820" (maximum magazine length)





Chronos

[Gwion]

Cheers Chronos. That looks like a good load you have there. Hope it doesn't take too much more development to find that consistent 1/2 Moa load I need for out at 500 and further.

[Gwion]

Huh HA!

Good news.... i didn't stick the whole bloody thing together with Devcon!!!

Quite happy with the way the bedding turned out so can spend today starting on the final clean up and finish of the stock. Should have it shooting tomorrow and continue applying more finish over the next few weeks. The finish i use sets pretty well so i can probably get 2 coats on today. Then it's:

One coat a day for a week,
One coat a month for a year,
One coat a year for life....

Recipe is equal parts bees wax and linseed oil (raw) slowly melted and not brought to boil, then add %50 by volume of mineral turps to thin for deeper penetration.

So, to the pics below. I started with a semi inletted walnut stock from Boyds. It was right hand because i couldn't get a lefty. My solution was to copy what Browning do with the T-bolt stock: each side is a mirror image so a a left or right action will fit in the same stock. Didn't work perfectly because i had to fill the right hand bolt recess with bedding compound to avoid having a point of intrusion for debris into the trigger mechanism. T-bolt being a straight pull, this is not an issue.

So mirror image for fitting the action, an over excited bit of floating the barrel and i't all ready for a fit and finish. I will also bed the floor plate in for a nice neat finish. I'll use some poly resin (fiber glass resin) with walnut sandings mixed in for this; add a bit of extra hardener and some post heat to speed up curing so that i can keep working on it sooner. Not recommended structurally but this is not a critical area and it's just a cosmetic fix.

Zastava Stock inletting 01.jpg (167.15 KiB) Viewed 6415 times

roughed out bolt recess for lefty conversion.

Zastava Stock inletting 02.jpg (148.45 KiB) Viewed 6415 times

Zastava Stock inletting 03.jpg (172.13 KiB) Viewed 6415 times

Zastava Stock bedded unfinished 01.jpg (223.78 KiB) Viewed 6415 times

Looks messy, but the bedding surface is nice and clean.

Zastava Stock bedded unfinished 02.jpg (321.99 KiB) Viewed 6415 times

PS: The king screws and the holes drilled in the semi inletted stock weren't a great match, so i reamed the holes out and used epoxy to set the pillars (provided with the Zasty action) into the stock before bedding.

Will update pics as progress ensues.

Cheers

[Gwion]

Oh....
And a couple of pics of the Howa with it's new barrel....

Unfortunately the barrel is way to thick for the Featherweight Thumbhole fore-end, so i had to basically destroy the aesthetics of the rifle to get it to work.

It will do until i can afford a nice GRS stock for it!

Howa 7-08 new barrel 01.jpg (333.52 KiB) Viewed 6369 times

Howa 7-08 new barrel 02.jpg (411.33 KiB) Viewed 6369 times

[Gwion]

SO, a bit more tidying up of the bedding prior to sanding and finishing.

Zastava Stock bedded unfinished 03.jpg (241.44 KiB) Viewed 6365 times

All sanded up and a good application of finish.

Zastava Stock bedded finished 01.jpg (197.2 KiB) Viewed 6365 times

Zastava M85 heavy barrel fitted and scope mounted. I'll continue adding more applications of finish but the walnut is starting to come out already.

Zastava M85 Heavy Barrel fitted.jpg (511.07 KiB) Viewed 6365 times

Tomorrow i'll adjust the sear engagement because i have it set a bit too fine right now; it fails the 'bump test' with a heavy blow to the butt plate with a rubber mallet. Then i'll do some loading and a bit of development and sight the little darling in.

Not too bad for a farm gun.

When it is rechambered to 223McShort it will look pretty much the same. It will lose an inch off the total length and i might get it Ceracoated or reblued; depending on funds available.

Now to get the thing shooting!!!

[Seik]

Ready for the Zombie apocalypse too I see

[Gwion]

Ready for the Zombie apocalypse too I see

Yep!
The 50gn Zmax shoot pretty well and work just fine. 21c each... only got 110 left out of 1000 i bought a while ago, so i'll be in trouble when the zombies come running!

Luckily i have best part of 1000 40gn bullets from a custom bullet maker in Vic. Their terminal performance is fantastic!

PS: initial load development has the rifle shooting well under an inch at 100m with the 50gn Zmax Will stick with this load for a while and see if it is consistent. 0.8MOA is just fine for this rifle.

[ebr love]

What bedding compound did you go with?

[Gwion]

I used Devcon Liquid Steel.

I have previously used Match Grade Bedding Compound from Terminal Ballistics Research in NZ, but with a pack of Devcon i get enough to do maybe 4 rifles/stocks.

Pretty happy with how it turned out.

[Heckler303]

Great thread to read up on, but there's something familar about your rifle and its new heavy barrel. Have you been to any ranges recently over the weekend and fired it off?

[Gwion]

Finally got around to finding a load for the 40gn VarmintR bullets in the 223 carbine.

26.2gn of BM8208 seems to be a sweet spot. Just a little concerned that 0.2gn either side was pretty crap so tolerances with both load and ambient temp might be tight. BM8208 is supposed to be pretty temp stable, though.

Test target below

image.jpg (1.79 MiB) Viewed 6187 times

[Strikey]

Looks like 26.2grns is your go to load, have you tried fiddling with the seating depth to see if the groups tighten up or not? I think you could probably tune a bit of the vertical out of it. I am not sure about BM8208's temperature sensitivity, its more like a narrow accuracy node with it, have been trying it in my 6BR and get the same results as you are seeing with your groups using Sierra Matchkings and Berger Columns, gave up and went back to 2208 & 2206H but my 250Savage seems to thrive on 8208 with a variety of projectiles.

[Gwion]

The 8208 worked a treat when that barrel was on the Howa. Tuned loads to about 1/2moa with three different bullets.

The seating is to max mag length, which puts me around 10thou to 20thou or so off the lands. I don't have the gear to get more accurate data of seating depth. Just find the lands and work in screw turns of the seater. 1/2 turn gives me about 20thou I think and I cranked it about 1/3 turn off the lands to max mag. Might need to crank it a little more because the rounds are a little tight in the mag.
It is a pest control round/rifle.

[Strikey]

Its all good then, make them fit the mag and feed reliably, should not miss too many pests with that combo

[Gwion]

Yeah... the feed reliably thing isn't working... might have to creep the bullet further in and hope the accuracy doesn't drop off.

Got a few last night out to about 140m but one of the rounds hung up in the mag and it stopped feeding ok. Had to dump them and single feed the last three rounds. Then i gave up and went back to the house.

[Gwion]

So.
I've been having trouble getting comfortable behind the 7mm-08 and it's been showing up down range at 500-600yds. Very inconsistent results. The inconsistency also has something to do with inconsistent neck tension, as some bullets where very noticeably more resistant on seating (all fire formed and neck sized now so that's not an excuse anymore). The biggest issue has be the comfort factor and just not being able to get relaxed and repeatably control the rifle shot to shot.

So, why? I ask myself..... i was 'comfy as' behind the rifle before new barrel and scope....

Ahhh... new scope.... different height for cheek weld and, as it is MUCH longer than my little old scope, getting the right eye relief requires that my head is further back on the butt stock.

I've come up with a solution and in dry firing practice it seems to have worked, even if it is a bit of a "farm yard" fix.

Length of pull has had 1" added to it and i added a very rustic version of adjustable buttplate for comfy shouldering with no torqing cant.

My improvised comb riser needed a bit of height added to it, so i used layers of closed cell foam. As it now looked even uglier, I also covered it in a bit of Auscam i've had lying around for years. It also needs to be removeable so i can get the cleaning rod down the barrel, so i velcroed it on.
Not the best solution, but it does work.

Pics below for your amusement.

BUTT in progress.jpg (215.96 KiB) Viewed 6933 times

BUTT finished.jpg (210.63 KiB) Viewed 6933 times

Yes, that is a cheap nylon chopping board from Woolies!

Like i said... it's not the prettiest or most glamorous solution but on my limited budget it will, hopefully, at least get me comfortable behind the rifle and get those rounds falling in the same spot...

The GRS stock is going to have to wait a LOOOONG time.

Cheers

[bigfellascott]

Nothing wrong with making stuff yourself, infact I love doing it, beats paying someone else to do what you can do with a bit of effort and imagination. There was an old fella at my local gun club who had a shotgun that looked like it was put together by Frankenstein, well all I can say it was butt ugly but he used to beat the ****** out of everyone he shot against, even with their fancy 10-20K shotguns!

[Gwion]

Yeah... she's a bit of a Frankenstein alright!

AS long as it works, i don't really care what it looks like. It's nice to have nice things but better to have something functional that you can use well.

The Mrs did have a laugh at it though... true back country craftsmanship (to paraphrase her comments).

[bigfellascott]

Yeah... she's a bit of a Frankenstein alright!

AS long as it works, i don't really care what it looks like. It's nice to have nice things but better to have something functional that you can use well.

The Mrs did have a laugh at it though... true back country craftsmanship (to paraphrase her comments).

That's it make it work for you regardless of look I say.

[Chickenhawk]

The Mrs did have a laugh at it though... true back country craftsmanship (to paraphrase her comments).

Is that like wife code for "you're an idiot"

[Gwion]

Pretty much

[Strikey]

I absolutely enjoy seeing some of the ingenuity people use to solve problems and save a few bucks, if it works for you mate, go for it and who gives a s**t what it looks like when you're posting some good scores/groups at those long distances

[Gwion]

Happy to report that the farm yard changes have made a marked difference to being able to get comfortable behind the 7mm08.

Managed a 50 & a 52 at 600 yards yesterday. Most consistent with the new barrel so far. Couple of rushed shots with poor wind reading and issues with a rest kept me from pushing the scores any higher.

[Ken]

Go the chopping board