Cases were initially sorted by weight into 0.1 grain increments. The selected ranges varied from 131.0 to 131.9 grains of dry brass weight. Twelve cases weighed in outside that range and were culled from further measurements. The weight sort produced a much flatter bell curve than I have seen with Alpha brass in the past. The 131.0 gr and 131.9 gr groups each contained 20 or so cases, while the bell peak was at 131.6 gr with 67 cases total. A weight curve of this shape is a bit frustrating because it frequently indicates a broad spectrum of case capacity which leads to significant vertical at distance unless a selection process is conducted.
To delineate that concern, case capacities were measured using a Sartorious scale delivering 0.002 gr +/- accuracy. A solution of one small drop of Dawn dish soap in one quart of water was used with a fine tipped dose syringe for delivery or removal of liquid to cases being measured. A 21st Century primer cup cap was used for each case with the plug being tissue paper dried before transfer between cases. Tare weight for this cap was 270.030 grains both before and after all measurements. Three cases from each weight group were arbitrarily selected and water capacity measured. Total fill was determined using a bright over head light to insure a flat fluid level at the top of each case. A totally flat miniscus can be obtained with the proper soap solution. A fine tipped syringe allows removal of any excess solution at the top of the case with aspiration. Many times you have to add or subtract a small amount of fluid to attain a level fill.
Average CC of the 131.0 gr weighted cases was 37.955 gr of H20 and the same measurement of the 131.9 gr weighted cases was 37.871. The variance rounded to 0.1 gr of H20 capacity between the lightest to heaviest cases measured. Average case capacities in the weight groups between the two extremes remained within the ES of the 131.0 and 131.9 groups.
To determine variance within groups, 10 cases from the 131.0gr group and 10 cases from the 131.9 gr group were arbitrarily selected and measured for case capacity. The 10 case average CC for the 131.0 gr group was 37.933 gr, while the 10 case average for the 131.9 gr group was 37.842 gr. of H20. ES in the 131.0gr group was approximately 0.1 gr and ES in the the 131.9 gr group was approximately 0.08 gr H20.
The predictive validity of case dry weight to actual case capacity has been a subject of many debates over the years. Measured numbers have been presented by many reloaders that argue both for and against the use of case weight to select for uniform case capacity.
There are several take-aways from the data reported here. Number one - Alpha brass is amazingly consistent Two - case weight may give some insight into case capacity but not always as much as we would like to believe. In prior case capacity measurements that I have done, there has always been an inverse relationship between case weight and case capacity. While one trends up the other usually trends down. I’ve usually found close to 0.1 gr to 0.1 gr change in weight versus capacity. That was not so with this particular batch of Alpha brass. Over a 0.9 gr variance in dry weight there was only an approximate 0.1 gr change in case capacity. Is that a fluke or is it further proof of Alpha’s quality control? I don’t know. Third - the recorded range of dry weights in this batch of brass would normally have prompted me to separate this brass into at least 4 different groups for competition reloading. These findings made me very comfortable dividing the total 388 cases in to just two groups making my reloading life much easier. So take-away number 3 is - there is no substitute for at least sampling case capacity in the competition brass you are going to sort. 😊 Number 4 - Alpha brass pays for itself.
As mentioned, these measurements come from virgin brass. After fire forming and uniforming case lengths, I will go back and repeat these measurements for comparison.
Disclaimer: please do not assume a 0.9 gr weight variance will produce this degree of consistency in case volume in a different brand of brass or even in a different batch of Alpha brass. This is simply a report on what I’ve found with my particular batch of brass.
I have a March 1975 Remington 700 ADL (LA in 30-06). The metal is pristine and the rifle has seen less than 50 rounds down the barrel. Unfortunately the forearm of the original Remington stock has enough warpage to be a functional deficit and I’m looking to restock with something in a laminate. All the offerings on Stockys Stocks are on back order, so I checked Boyd’s and found several available.
Can someone with personal experience give me their pros and cons on the Boyd product? I would be using their Heritage or Classic stock, not the new fancy all in one that they recently start making. Thanks.
It’s encouraging to see the advent of two new major national competitions scheduled for next year. @rardoin has described the new F Class event:
“An F-Class Points Series event, the V² Finale is conducted as a 3-day tournament, with exceptional sponsors. Points, seed rankings, and invites are based off of competitors year long performance at qualifying LR matches around the country. In 2021, the V² Finale will be held 11-13 of June at Dead Zero Shooting Range in Tennessee.” (from rardoin)
This info sounds like the hoops you might have to go through to qualify for the PGA Championship. Conversely, the up coming new benchrest competition might be more like the US Open golfing event.
The “Longrange Rendezvous”is open to all shooters who register before the 98 competitor limit is reached. Through the four day event, each competitor can only use one rifle under 22 pounds. Aggregate scores will be used to select a list of 14 shooters who compete for final honors. Scores will be entered from 16 targets, shot at either 600 or 1000 yards. The top 14 competitors will do a shoot off for the final 7 positions to determine winners. The competition will be held at the Vapor Trail Valley range in Missouri June 16 thru 20. Several of us from this forum have gotten our registrations in and I believe a few more spots are still open. The total registration fee for the week is $350: $200 pre-registration followed by $150 at the match. The competitors who are coming, hail from just about every state in the nation - they are the cream of the crop. I am going to put my best competitive foot forward, but will consider it a win just to meet and shoot with some of the very best long distance benchresters in the nation. It’s a long trip requiring a lot of preparation and time commitment.
Dadajack posted earlier that he has a 308 Christiansen Arms in the near future. Got me thinking about the cartridge. Started a list of pros and cons in my head. The most obvious pro is ammo availability. Curious what others would list as pros and cons.
Since then I’ve remained a follower and fan of their efforts devoted to simply producing the best brass available for reloading. Recently they modified their brass production to develop what they call OCD brass. For obvious reasons I knew they were my company of preference with something carrying a reference to “obsessive compulsive disorder”. 😂 Actually it stands for “optimized case design” and it’s not just a marketing ploy - these guys are dead serious about minimizing primer pocket degradation with multiple firing cycles. Read up on it if you like because I’m digressing from the subject of this thread - flash hole diameter.
Alpha recently got into the production of the BR case and it’s variants - BRA, Dasher, etc. Interestingly, their cases came out with a 0.080 flash hole diameter instead of the traditional 0.059 or 0.060 flash hole found in Norma and Lapua offerings. This bothered me, but I purchased anyway because it’s Alpha brass and I wanted their quality for my efforts in competition.
Late last week my curiosity got the better of me and I reached out to Tom and Bob at Alpha with the question - why the larger flash hole? Got my answer today from Bob. “Better, more consistent ignition”. To me that should correlate to lower SDs which is always a worthwhile quest. Bob tells me Alex Wheeler is doing independent testing to document that statement and will publish his results soon.
WOW - I think this is another example of Alpha’s quest to push the envelope and not just follow accepted tradition. Great company!
Well it’s been a crazy year, and it’s not quite over yet.
To all of my friends here:
Merry Christmas to you and your family, from me and mine! While we put our stress and worries aside for a heartbeat to celebrate Christ’s birth, I hope you all find a little of the peace and joy of the season. It’s a good time to be thankful for even the things we take for granted.
This forum has been a source of knowledge and camaraderie for me almost every day of the past year. Thank you for the sharing and friendship. And a special thought of appreciation to Carlos for providing the site and our three great monitors for keeping us focused and moving forward.