Thoughts On A Custom .223 Reamer (New Build)

[Rust]

Didn't want to hijack anyone elses thread.

I will shortly be ordering a chamber reamer, floating pilot set and gauge for a new build. The intent is to have a .223 bolt rifle capable of shooting to 1,000 yards.

The plan is to aquire a large quantity of brass from a single batch, and load up a couple of dummy rounds to as a pattern to grind the reamer to. Since it is a bolt rifle, single feed will be the order of the day do COL will not be a limiting factor.

I am considering going with a .003" or .004" neck clearance for no-turn brass, provided that the neck thickness uniformity is good enough on the batch of brass. Has anyone done this and are there any thoughts on it?

In my .308 and 6.5 X 284 the leade angle is 1-1/2 degrees which works fine in the larger cartridges but am considering less angle for the .223. Would 1-1/4 degrees be a sensible compromise between keeping pressure down and throat/leade life?

Since it is going to be a bolt gun, the plan is to go with a fairly tight chamber, are there any know issues with such a thing?

What are the more popular 80 gr bullets? I realize that there is considerable difference in the physical dimensions of the bullets, which affect seating depth to hit the lands, and that the most suitable freebore for one bullet may not be ideal for another. Further, seating further into the case affects case capacity and thus the suitable powder charge range. I'd like to start with the chamber optimized for the most most commonly successful bullet. Suggestions on bullets?

I look forward to your comments and suggestions. Suggestions to stick with a different cartridge don't count, I already have four other 1,000 yard chamberings ;D

 

[Laurie]

Rust,

the Hornady A-Max is generally considered the best of the 80s, providing it's from a good production batch.

Why restrict yourself to an 80 though when Berger makes a superior 90gn VLD that offers a step change in external ballistic perormance?

Jerry Tierney has been doing a lot of testing at Sacramento with both 80s and 90s in a Palma rifle and getting good results, the 80s at up to 3,100 fps and the 90 Berger shooting very well at around 2,830 fps in his rifle. At that MV, .223 / 90VLD outperforms any 155gn .308 Win load and is only marginally behind .308 with 210gn VLDs at 2,600-2650 fps so far as wind deflection is concerned.

Jerry T has written his results up in detail on the US Rifle Teams Forum:

http://www.usrifleteams.com/lrforum/index.php?showtopic=11795

http://www.usrifleteams.com/lrforum/index.php?showtopic=11997

http://www.usrifleteams.com/lrforum/index.php?showtopic=11444

It seems that an important part of getting 90s to perform well is not to use an overly fast rifling twist - the 1-6.5" recommended by Sierra for its 90gn MK is not a good idea, it seems. Mr Tierney recommends 1-7", although he was using a 1-7.7" in his Scaramento Range tests, and just got away with it with the VLDs at MVs above 2,700 fps. The 90gn Sierra has also been known to break up if pushed too fast - it seems it was designed for XTC shooting at a max MV of 2,600-2,650 fps.

I'm trying this route myself for my F/TR rifle for 2010. The reamer (PT&G) is based on a Lapua match case with the Berger 90 VLD seated to give a COAL around the 2.7" mark. If it doesn't match my 308 at long range, it should still make a very good 300-600yd F/TR round. The benefit is recoil reduction - around a quarter of that of a full-house 308 load in an 18lb rifle improving rifle handling on the bipod and bags.

regards,

Laurie,
York, England

 

[Rust]

Laurie - The decision to go with the 80 gr class of bullets rather than the 90s was made after more than a little consideration. I felt the odds of a successful build in a shorter time frame were greater going with the 80s.

 

[msnations]

I've always had good success with berger 80 vlds and their 82 bt. I feel that they are a step above 80 matchkings and a-maxs...

i haven't been very pleased with any .223 brass i've gotten over the past couple years - it all needed to be neck turned for long range performance (out to 300 yards it was fine as-is).

I'll have to dig up the freebore length specs on my reamers...

 

[Rust]

MS - I woud appreciate the information.

As mentioned, I would like to avoid neck turning brass while at the same time tightening up the clearances. Do you use a tighter neck diameter in your chamber?

 

[1000yardstare]

My 30 inch 8 twist Wylde chambered .223 MacLennon barrel shoots 75 AMax the best which are a little light for beyond 600 yards. The best 80 is the MKing. No matter what bullet is used, you must be an excellent wind reader beyond 600 yards to place well with a .223. Also you have to resist the temptation to load to extremely high pressure trying to milk the last foot per second out of that dinky case. I have seen stuck cases and pierced primers in F Class practise and competition because of these high pressures.

A .223 placed very high in F(F) which is very similar to F(TR) at the 2009 Canadian Fullbore Champs. The chap was shooting against .308s and very nearly beat them all but this shooter is an excellent wind reader. Much better than me which is why I have switched to a 6AI and shoot in F(O). My .223 is pretty well relegated to 300 metre ISU shoots.

In case you didn`t spot it, here is a chart of the various .223 reamers
http://www.ar15barrels.com/data/223-556.pdf

 

[fdshuster]

Rust: regarding chamber neck dia.: I'm using 223 Lapua brass with a loaded round neck dia. of .250", and had Pacific make a chambering reamer with a .253" chamber neck. 3 chambers cut with that same reamer now, and it was a good choice, for me. 80 gr. Sierra MatchKing is my "standard" long range bullet, but to me, long range is 500 yd., not even close to where you want to go, so really can't comment on that.