300 whisper/BLK semi custom build have some quest

[Dubs Chops]

OK here is the rifle and the details.

Savage stevens 200 with a 16.5" Match McGowan barrel 1/8 twist 16.5"
Cdi bottom metal for AI mags
10 rnd AI mag that holds 11 rounds of .300 Blk
Bell and Carlson Medalist Varmit stock Inletted By CDI for their bottom metal.
Sharo Shooter Supply Tactical volt handle
Sharp SHooter Supply 1.5" trigger (still to come its backlordered"
Vortex Viper 6.6-20X44 BDC reticle
Tactical Works Inc, Tac Ops ammo cheek pad
Muzzle break made to order from a guy off of Ebay for a whopping $65 and its stainless.

The Problem is I took it out yesterday to get it sighted in at 100yrds. got it to where the first shot is dead on,

then I started 3 shot groups. 1 shot right on, second one is about 3" low and the next shot anywhere from 4-6" low. I am assuming this is from barrel heat but I am using subsonic loads that produce very little heat on the barrel. I would feel the barrel and it was probabbly only 20* more than ambient that was about 89* these were handloads from someone else but they were doing this same thing pretty consistently. it is a 200 gr sierra game king bullet.

Any ideas on what could be causing this?

 

[RedGoat]

Re: 300 whisper/BLK semi custom build have some quest

The rounds might be loaded inconsistently. Also might want to try the 220RN they do more damage than the pointed bullets (wish they fed better in my AR).

BTW very sweet rig, looks very handy. Load that thing up with some 110gr TSX and it will thump some critters.

 

[onyx1357]

Re: 300 whisper/BLK semi custom build have some quest

I would say ammo isn't loaded like a match round or get a chrono out and see if your in the supersonic one shot and not on the next

 

[redbullitt]

Re: 300 whisper/BLK semi custom build have some quest

Gotta point to ammo there man. Any idea on the load data? The 300 blk I have shot (even sub 308) has shot better than that.

Not a barrel heat issue.

You mention the discount muzzle brake, any chance it could be out of spec?

Might be a good idea to try some factory loads to get a baseline.

 

[Dubs Chops]

Re: 300 whisper/BLK semi custom build have some quest

the muzzle break doesn't get shot. it is just there to keep the threads from getting jacked up when My can is on something else. I will try the factory rem subs I guess and see what happens.

Thanks fella's

 

[BenY 2013]

Re: 300 whisper/BLK semi custom build have some quest

That is an awesome looking gun! I am wanting to do a .223 like that very soon!

 

[wfjames22]

Re: 300 whisper/BLK semi custom build have some quest

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dubs Chops</div><div class="ubbcode-body">I will try the factory rem subs I guess and see what happens.</div></div>

I wouldn't count it out if the Remington factory subs don't shoot great, as I have a buddy that had them shoot like shit out of his gun. I bought 3 boxes of them and ran them through my Daniel Defense AR and they seemed to do fine accuracy wise, but I didn't put them on paper. I only shot them on steel out to 300yds and they shot pretty well.

 

[aubie515]

Re: 300 whisper/BLK semi custom build have some quest

Nice rifle...I'm going to be doing something similar...I won't get the Medalist stock or high magnification optic, but I plan on using a CDI for my 300BO build.

 

[biffj]

Re: 300 whisper/BLK semi custom build have some quest

Ammo is pretty critical and so is getting bullet seating right. Remember that when shooting the subs you're looking at loads where a tenth of a grain can make a huge difference. Some guns like the faster powders and some slower. (2400, N110, 4227....) We have found that the loads using H110 are all over the place even when the powder charge is within a hundreth of a grain. H110 works great in some loads but usually when its full case or so. In a partial case charge it will not work too well and temps change things a lot too. I had one rifle that needed bullets seated on the lands to get the group down to size while another preferred about .015 off the lands. Some guns prefer crimped necks and others don't....
It will take some doing but you can get a load set up for the rifle. Don't worry about heat....there isn't much until you start loading hot supersonics and even then you can only fit so much powder in the case. The issue you're having is most likely ammo related.

The Brake looks neat but is completely useless for anything but what you're using it for....a thread protector. If you don't have enough muzzle pressure you won't get any braking action. With this round loaded supersonic you won't likely have any help from the brake so it won't help at all with subs.

Neat build

Frank

 

[a220stw]

Re: 300 whisper/BLK semi custom build have some quest

i built a blackout on a remington XCR tac action. used acc barrel. sighted in with 220 remington and 208 whisper from hornady. mine shoots great.
maybe just try some differnt ammo and make sure everything is tight. best of luck to you

 

[mavrick]

Re: 300 whisper/BLK semi custom build have some quest

Like Biff was saying powder choice with subs makes alot diff. I settled in on Lil gun with 220 SMKs I also had good results with N110.

Dustin

 

[Dubs Chops]

Re: 300 whisper/BLK semi custom build have some quest

lil gun is what we are going to load our ammo with at first and see what the rounds shoot like. I'll get back with you guys after new ammo and see what happens.