Chrony Help Please

Hi Guys and Girls,

I'm in need of a little help. I'll spare you my life story but here is the short version.

I have Kimber 84M in 7mm08 with a 14" barrel and DPT which I use for bush hunting over my dog. I also have a 7mmRM for longer stuff which is away getting a new Stug stock hence the problem. I am heading away chasing sika next weekend and will definitely be in an area with longer shots being needed.

I can shoot and have an accurate load for the bush pig which has proven drops with a good dial up scope. Problem is the load I have is only good to 300yds max using a very slow 150gn projectile (before it runs out of energy). I can no doubt get more velocity out of the same powder and same projectile combo but have never had the need so don't have a load or drops.

I also have the option of running 120gn SPH pills over the same powder AR2208 (not that keen to buy new powders and pills for a once off).

Now here comes the main problem - I have a suitable location to do some shooting (weekend only)but no confidence in my Chrony. It is one of the cheap "Shooting Chrony Alpha" models I brought second hand and seems to read extremely high (I ran my rem mag over it, which I know to be doing 3050fps, and it recorded 3600fps). Being one of the fold out chronys it does not seem to be fully folded flat (thus shortening the distance between sensors and) which would account for the high reading... Anyway I digress.

I have two main questions:
Firstly - Which pill is likely to get me the best performance out of the 14" barrel (velocity and killing at range)? What realistic velocity can I expect with the 120s and the 150s over AR2208?
Secondly - Anyone between the Harbour Bridge and Whangarei got a chrony I can borrow for the weekend?

Cheers,
Adam

pm inbound

stalk closer :D ive got a chrony but 2 problems are its the same as yours and my mates got it and hes in cambridge this weekend for the armistance thing could always try them side by side sometime and see how they go

Ok so thanks to @chainsaw I have a crony to borrow for the weekend.

While setting up my reloading kit I found some projectiles I forgot I had - 140 SGK and 162 A-Max.

Thinking I'll try squeeze as much velocity out of the AMAX as possible. Any thoughts on how much speed I might get? Anyone else using big pills in a bush pig to good effect?

With a 14" barrel you'll be limited to a little over 2400 ft/sec with a 150gr bullet and AR2208 anyway. I'm not sure that changing either the bullet, powder, or quantity of powder is such a good idea at short notice, borrowed chrony or not. If the load you are using is one you are familiar with in term of accuracy and drop then I'd think that the confidence that brings trumps any likely gains in on-paper effectiveness from tweaking things?

Good point @Puffin. I still have my 150gn pills loaded anyway, so provided I note down my adjustment if I re-zero I can always come back to it and shoot the bush loads.

Shooter says I'll get 1000ft/lb. out to 475yds if I can get the amax to 2250fps. You reckon that's feasible?

whats the muzzle flash like, going to a faster powder will minimise muzzle flash but will better use the powder and may get some more speed.

Dunno @mucko, never noticed it... perhaps the suppressor removes any flash

How close to the muzzle is the chronograph when you shoot through it?

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Originally Posted by bully

How close to the muzzle is the chronograph when you shoot through it?

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about 3-5m

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Originally Posted by Dorkus

Shooter says I'll get 1000ft/lb. out to 475yds if I can get the amax to 2250fps. You reckon that's feasible?

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I think so. Work up to 39gr of your 2208. Might get there with 38gr.

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Originally Posted by Puffin

I think so. Work up to 39gr of your 2208. Might get there with 38gr.

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Unless I'm doing something badly wrong, in which case I should stop now, I'm reading a starting load of 38.5 of 2208 from the ADI manual.
Load data for AR2208 and 162 Hornady A-Maxhttps://uploads.tapatalk-cdn.com/201...a07144fd38.jpg

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Take the bush load and treat it as a challenge:thumbsup:. Where you hunting?

That is for quite a long CoL. I think you will be limited to 2.820" in the Kimber, maybe a little less, in which case I wouldn't jump in at 41gr. Shorter CoL will crank up the peak pressure. Try 38-39gr. I think you will be close to your target MV. Remember too that you will be 250-300 ft/sec down on a 22" barrel. That is probably the length used for the book figures.

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Originally Posted by Dorkus

about 3-5m

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Seems about what I use, 4 mtrs for a magnum, no less.

Have you sold the 6.5?
Borrow a rifle off a good bugger from Auckland area..... oops you already have a 7-08:oh noes:


Seriously mate do you want to borrow one of mine for your trip?

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Originally Posted by Shootm

Have you sold the 6.5?
Borrow a rifle off a good bugger from Auckland area..... oops you already have a 7-08:oh noes:


Seriously mate do you want to borrow one of mine for your trip?

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Yeah mate I'm selling down. Cheers for the offer but I'm happy having a play today to work out something that will give the pig a bit more reach.

Won't be long before my rem mag is back from Stu and I'll have everything covered.

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Originally Posted by Dorkus

Dunno @mucko, never noticed it... perhaps the suppressor removes any flash

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try without can and see if you get a flash, ive got some 55gr pills shooting out of my 243 at 3900ft/sc using 2208 theres a huge flash so im going to a faster powder.

waaaaay back the NZHunter guys did article on bush pig (hate that term...its what ugly shelahs were called when I was a young fella) CARBINE length rifles and loads....long and short of it they dropped down to 100-120ish grain barnes type loads to regain speed with preformance to stretch distance that little bit more...if you know where your current load is at 300 etc you could make that 400 yard hit and do it again doubling the effect of projectile on animal.... chances are you going to be all set up for the long shot and tumble a big fat spiker at spitting range to shoot anyway.....

@Dorkus What I have found using several different chronos is that none of them seem to be correct with varying degrees of incorrectness. No matter what any chrony says my speed is I will always drop test it and validate velocity that way. If at all possible I would do a drop test at 300 m before you head out on the hunt, maybe you can find a 300 m relatively flat line of sight at the hunt location before you walk in. Everytime I do this ( I repeat after reloading every batch of 100) I get a different answer to what the Chronograph says, and using the drop test validation has never let me down with long shots subsequently. I have learnt the hard way never to trust the chrono velocity, that said I've not used one of the expensive ones like a Labradar or Magnetospeed.

So I spent half the night last night getting my reloading kit all set up (hadn't used it since moving back to Auckland earlier this year) and loading up 3x 20 different loads. These were a mix of pills - 120gn SPH, 140gn SGK and 162gn A-Max all over 2208.

I started with the A-Max because it's the one I wanted to work. I seated them out as far as I could, didn't measure the jump but it's not much. My target was accuracy better than 1MOA and velocity over 2250fps without too much pressure.

I started conservatively at 38gn 2208 on the advice of @Puffin, noting my overall length was shorter than the book recommendation. That shot okay, as did everything from 38-42gn. 41gn was particularly good, with very little ES and all shots touching with only lateral movement. I worked up slowly to 43gn (41 being book max) and started to get a little bit of head stamping, nothing drastic and bolt-lift was easy and primers were still nice and rounded with no excessive cratering.

I settled at 42.5gn which chucks the 162 pill at 2285fps and lands them in a neat little clover at 100yds.

I'm not going to bother shooting the either of the sierras, can't see much point. Plus it's windy and I have a headache. I'll take a few more photos when I can be bothered pulling my targets and writing it up.

Cheers to the good buggers who offered their opinions and ideas. @chainsaw who lent me his chrony and @Danny and @Shootm who offered to lend me bang sticks for my hunt if I couldn't get my shit together... This forum is awesome!https://uploads.tapatalk-cdn.com/201...bafb7d2ce0.jpghttps://uploads.tapatalk-cdn.com/201...5508ae17fa.jpghttps://uploads.tapatalk-cdn.com/201...099c8afc81.jpg

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My targets from today... she was a bit blustery to start with but it looks like my shooting got a bit better but the A-Max seemed to like that 41-42.5gn zone. Not sure what caused the massive ES on the 43gn string, maybe my loading (2223, 2117, 2303)? As I said above pressure didn't look all that high. https://uploads.tapatalk-cdn.com/201...a5a195d115.jpghttps://uploads.tapatalk-cdn.com/201...3c41748e50.jpg

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