My new thermal build, looking for suggestions

ScottyP

New member
Ok guys I’m currently building an AR10 for my new thermal rig. I have thermal hunted the last few years with a .22-250 bolt gun. I really love the caliber and how it preformed on yotes. I wanted to switch to an AR, since the .22-250 isn’t really feasible in an AR, I decided on the .22 Nosler. I knew I would have to reload so I have spent the last year studying up on that and buying my press and other tools. Somehow, While shopping online for a barrel, I found a steal on a brand new Shaw 22” 1-10 twist heavy barrel in .243 win. I snagged it and now switched gears towards an AR10, I added an Aero high profile upper and handguard with the Aero bcg. Now that the upper is done I need to finish the lower.
I am planning on sticking with Aero and going with an M5 stripped lower. I believe I want a decent Trigger tech trigger but I am open to suggestions. I want a decent stock with no rattle, looking at a Luth AR MB series. Does anyone have any suggestions for anything different I need to do with this lower? This is my first AR10 build.
Since this will be a thermal only gun, I am hoping to make it shoot faster lightweights. I really want it to be a laser from 0-300. I do cherry pick and skin the good yotes so I’m not trying to destroy every one. I do realize the .243 isn’t exactly “fur friendly “ but I don’t care to explode all of them. After a lot of research, I am hoping I can find a load for the Sierra 60gr Varminter Hps. I also have 65 gr vmax, 55 gr Nosler BTs, and cutting edge 60gr extended range copper bullets to try. The powders I have on hand are Varget, H380, Superformance, CFE223, IMR 4895 and H335. Im a beginner reloader with a Lee Breechlock single stage. Does anyone have any other tips, tricks or load combos that I need to be looking at for this gun?? Im hoping I can come up with a decent load with what I have. I know this isn’t going to be a “Gucci” or top tier rifle, but I really want to maximize the accuracy and performance that I get out of it. Thanks for any input. Wish I knew how to post pics of the upper.
 
I shoot 60gr Sierras in my 22 DTI. Your .243 is going to be faster ( mine is 3450fps) but I usually don not have a pass thru. They are DRT.

On reloading most of the time the powder that fills the case the most is usually the most accurate. Be sure to work your way up to the maximum load from your reloading manual starting from the minimum to maximum looking for signs of pressure.
 
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That’s good too hear on the pass throughs. I have been shooting factory Superformance loads out of my .22-250 with 50gr v-max pills. When they work right they work great, but at almost 4000fps I get a lot of splashes and they aren’t pretty. I’m hoping the HPs work out better.
 
I built a 243 in January. I went all Aero with a 24 inch McGowen. Ive only shot it at night and need to put a glass scope on it and really see what it can do. I loaded 48 grain win. 760 with 58 grain v max. It’s accurate and really hard on coyotes. I’m going to work on a load slowing it down a little. I like an adjustable stock and use Hogue. They put rubber on the stock that fits snug against the buffer tube so no rattle and warmer on the cheek in the winter. It looks like you have a bunch of load options in mind. I agree with old cat, start at a minimum load and see what works.
 
I bet your vmax are moving pretty good with the 760. I wanted to try a pound of 760 just because it seems to hit crazy speeds with decent accuracy in lightweight 6mm bullets. I got a little spooked reading about how temp sensitive it can be. Have you had any issues with that?
 
So something you need to consider is proper cheek weld. Since you used a high rise upper, this could be an issue depending on the type of thermal. 99% of the thermals out there are specifically designed for regular height ARs and close to 3" above the bore so you may need a stock with adjustable cheek piece. Proper cheek weld is SUPER important, even with thermals.

As for loads, I only consider temp stability powder. Varget is my number one choice and H4895 is good as well. If your saving fur try the 55 or 70 NBT, Hornady 58,65 and 75Vmax.

243s are super over gassed so get an adjustable gas block.
 
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Originally Posted By: ScottyPI bet your vmax are moving pretty good with the 760. I wanted to try a pound of 760 just because it seems to hit crazy speeds with decent accuracy in lightweight 6mm bullets. I got a little spooked reading about how temp sensitive it can be. Have you had any issues with that? When it gets in the 90’s I can tell it’s a little hotter but don’t have pressure problems and accuracy is good. I use CFE223 also. I try to stay away from stick powders.
 
If a person hunts in an environment where the temperature doesn't fluctuate much, ball powders like CFE223 and 760 are great. They flow like water when using them in a powder throw or progressive unlike extruded stick powder BUT, if you hunt big temperature swings it absolutely will effect your zero much more drastically than extruded. I live in Southern Indiana and in January it can literally be 0 degrees and 65 the next night! Happens all the time so temperature stability is of the utmost importance to me along with accuracy.

If a person lived in South Texas where its warm 99% or the Dakotas where its cold all winter ball powders is definitely an option.
 
55 gr Sierra over Varget. Stay off of bone and you'll have to skin them to find the entrance wound. Seldom exit and even then it's just a sliver. .243 rocks!
 
When you say 55 Sierra, are you talking Blitzkings? I really wish Sierra would get caught up so I can buy both Blitzkings and Varminter HPs. I haven’t seen the. In a shelf in two years. I snagged a few boxes of the HPs on gunbroker. Overpayed for them with shipping but there weren’t terrible gouging prices.
 
@ ScottyP
Acronin here on PredatorMasters recommended those .243 - 55 grain Sierras Blitzkings. They are pure poison on coyotes. If you stay off bone, they look like they were hit by lightning...almost no damage. Absolutely outstanding. After trying them out on coyotes and smaller critters, I bought a thousand of them. Wish I'd doubled that order.

I've been shooting them for a year and a half. Over 80% don't exit and damage is minimal when they do. Put it behind the shoulder and in front of the hips and you'll get bang-flops. Put it on bone and you'll still drop them but entrance damage is tennis ball size holes. I've shot 30+ coyotes with them and I've had one hit that got away. After reviewing the video, I'm convinced the shot went low and broke the off side leg. Can't blame the bullet for poor shot placement.
 
Also, you should heed Kino's advice on powder heat sensitivity. I've noticed it with CFE 223 and read bad stories about Win 760.
 
Night hunting is basically a 300 yard and under game. The 243 will be a laser with any 55 to to 70 grain bullet. I think 70s are the best weight/velocity compromise. At 300 and in I would pick the fastest accurate powder. I would not over think it. Most thermal scopes will cause more shift than any other factor. That high rise upper is gonna be the biggest issue imo. You might even need to sight in a tad low at 100 to keep from being too high around the 165ish yardage area were most coyotes get shot. Gonna be pretty low if one gets in your lap too. Sight in a bit high at 100 and you will have a near 300 yard zero.
 
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I night hunt on a farm in Ohio. So I use a 300 Blackout.
I used an ATN 4K but I bought an ATN Thor 4.
People around me do not like to hear gunfire at night.
I have been shooting the 208gr SIG ammo.
 
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