Posts Tagged ‘AR-308’

Range Results: AR-308 rifle – getting close to goal

Thursday, March 29th, 2012

Hey everyone- I’ve had quite a few inquiries as to how the range results are looking for the AR-308 project rifle. I didn’t set a formal accuracy goal for the project, but I would like to see consistent ~0.5″ groups at 100 yards. This involves shooting skills, load development, and time.

This last week, I was able to spend some time at the range (it wasn’t raining, in Seattle that’s remarkable this time of year) and was pleased with how the rifle was shooting.

I only had time for a few groups (I was there working on an upcoming project for NWGUN as my primary activity) but I was able to shoot a 0.7″ group with one flinch-induced flier, and four shots in ~0.2″.

AR-308 Group at 100 yards - 5 shots in 0.7", 4 shots in 0.2"

These shots were fired off a bipod on the front, and with a wooden block and improvised stock hold on the back. I saw the reticle move off target when the flier was shot, and I thought to myself- “Aaaaaaaaarrrrrgh” (think Charlie Brown voice). It’s always that one shot! :)

Based on these and other results, I’m confident that I can attain my “consistent 0.5 inch @ 100 yards” goal. I think the biggest thing at this point is to spend more time at the range.

Loads you ask? (that’s the point of this site, right?). These were my military-custom-match loads. These loads were assembled with carefully prepped 7.62x51mm military brass including case neck thickness/uniformity sorting.

Best load of the day - Military brass with XBR and 168gr Hornady HPBT

Here’s the load specifics (use at your own risk, always cross-reference load data before using!)

Brass: Military 7.62x51mm, case neck 0.016” +/- 0.0005”
Powder: IMR XBR – 40.0 grains
Primer: CCI BR2 Bench Rest
Bullet: Hornady 168 grain Match HPBT

These were my first loads with IMR XPR powder, and it looks like I’ll be using this powder and load to “hone in” on an optimal load for this rifle. Without the flier, I could have been in the 1/4″ range for a 5-shot group. Perhaps next time!

Thanks,
Gavin

AR-308 – Precision Loading Pt. 4 – Seating Bullets Checking Concentricity

Thursday, October 27th, 2011

In my last video, I covered priming and charging cases, see AR-308 – Precision Loading Pt. 3 – Priming and Charging Cases. Now we need to seat bullets, and also check/correct for concentricity of the bullet. If we have a consistent charge, a benchrest primer, consistent case neck thickness, and a properly/optimally seated bullet, we’re going to have some mighty fine results (especially considering the rifle that we’re using).

More details to follow! My next set of posts in this series will cover progressive reloading equipment and the RCBS Bullet Feeder for 30 cal. It’s going to be fun!

Thanks,

Gavin

AR-308 – Precision Loading Pt. 3 – Priming and Charging Cases

Sunday, October 23rd, 2011

In my last post, I walked through the process of using the Redding Case Neck Gage to sort our 7.62×51 (Military 308 Winchester) brass into buckets based on both thickness and uniformity. Below is a picture showing the distribution. The numbers I’m using here (0.016″ +/- .0005″ for example) reference the total variation in thickness, so this is really +/- .00025″ if you want to get literal. Pretty decent! I’ll use the brass with more case neck thickness variation for progressive loading, or possibly even to turn the case necks in the future. For now, we have some great batches of brass to work with.

Sorted 308 Winchester Brass - Image Copyright 2011 Ultimate Reloader

Now it’s time to prime the cases on the Redding Big Boss II, and then to charge the cases. For these loads, we’ll use a new powder called IMR XBR 8208. I’m excited to see how this powder performs with the LR-308B!

IMR XBR 8208 Powder - Geared towards benchrest shooters - Image Copyright 2011 Ultimate Reloader

And here’s the video showing the process of priming the cases on the Redding Big Boss II, and charging the cases with the Hornady Auto Charge.

Next, its on to seating bullets and checking/correcting concentricity.

-Gavin

AR-308 – Precision Loading Pt. 2 – Case Neck Thickness and Uniformity

Tuesday, October 18th, 2011

Now that we’ve cleaned, sized, trimmed, and finished the basis brass prep steps, it’s time to sort the brass that we’ve prepped so that we can uses batches of consistent brass for precision loads. We are now at the final stage of brass prep as covered in the brass prep overview post.

For this stage, we’ll use the Redding Case Neck Gage (Redding #26400).

Redding Case Neck Gage - A tool used to profile brass for utmost accuracy - Image Copyright 2011 Ultimate Reloader

Here’s a video showing the process of using the Redding Case Neck Gage to sort some once-fired 7.62×51 brass that I’ll be using for the AR-308 project:

Now that we’ve wrapped up brass prep, it’s time to move on to the next steps in the precision loading process. I do enjoy this kind of loading. With all of the precise tools at hand, some times I feel like I need to put a white lab coat on- kind of fun.

Stay tuned- we’re going to have fun finishing these loads!
-Gavin

AR-308 – Precision Loading Pt. 1 – Case sizing and trimming

Sunday, October 16th, 2011

It’s time to start loading some precision 308 Winchester ammo for the LR-308 project! Our rifle is all tuned up and tricked out, and now we need some capable ammunition to shoot.

In this video, I’ll walk through the process of validating sizing die setup with the new Redding Instant Indicator, and we’ll see how to size cases. Following that, I’ll show using the Hornady Case Prep Center to trim the brass to length, chamfer the case mouth, and also ream the primer pocket (an important final touch when working with military brass like the 7.62×51 once-fired brass that I’m using for this project).

Next, we’ll use the Redding case neck gage to sort cases by neck thickness and neck uniformity.

Thanks,
Gavin