Possibility of getting 1.550" case length or so after FF a 6 Dasher?

[jjhall91]

While it's not proof by any stretch. At a time I shortened up my reamers on purpose for this very reason. I struggled with a handful of barrels. I concluded, without proof, that chamber length was the only change I made to cause those struggles. I went back to the longer chambers and wound up back to great barrels one after another again. This was years ago, and not scientifically proven, but is my experience. I also had those same thoughts/theories back then, and is why I tried it.

Tom

Well, if not actually out-and-out proof, it certainly is in that category. Especially because it was tried on barrels (plural).

Would you mind giving your impression/opinion regarding what is a short chamber as compared to a long? That or even better, what was the short trim length that didn't seem to shoot as well along with the long trim length that shot better?

These things help me a great deal.

Thanks,
Jack

(Just returned from shoot 5 FF cases. This is one example. Somehow, it doesn't look very concentric.)

 

[tom]

Jack,

My experience was sort of "coarse" so to speak. Started shooting dashers on a print specified 1.570", but it cut closer to 1.580". Had wonderful results on multiple barrels. After a few years I decided to get my own reamers, and was sure I was going to outsmart everyone else. I specified them for 1.555", and those all cut really close to exactly that. A couple years went by of struggling with multiple barrels. I then tried a br-dx for a while, and those were all 1.555". Again a couple years of struggling, although they would shoot small on occasion. I finally gave up on the cartridge, but also recognized the chamber length as a possible source of the consistency problems. Went back to 1.570" dashers, and shortly thereafter 1.570" BRA, been in the hunt for aggregate records ever since, whether I come up just short, or just barely beat them, the consistency is there. I wouldn't venture a guess as to where exactly length clearance becomes to little....best idea is it's somewhere between there and there lol. I tended to trim around 1.540" on my brass throughout all them years. With the exception of hydro formed dasher cases, which wound up down around 1.535"....and btw were clear to me my very best dasher years.

Tom

 

[Rset]

You just keep believing that...... BTW were do you compete and how often do you win to make those kind of statements?? ..... jim

Not as good as some, but I do OK

 

[Rset]

Thank you, Rset. Glad to hear that about accuracy not being effected. I honestly can't say I can tell the difference in accuracy to the many different case lengths I've tried. I've even shot loads that varied .005 in length and had good groups (good to my standards anyway).

I have a scope and the carbon does seem a slight bit worse when using lengths less than 1.4200 or so. But I can't say with certainty.

Could I ask you what the shortest length you'd shoot? I have some in the 1.4000 range that I've never dared to shoot. Is that too short?

Thanks for the help!

Jack

Let your rifle tell you what works. If the neck is long enough to secure the bullet you are off to a good start. Depending on your chamber, you may have some issues with seating the bullet to your desired length, but if you, your rifle, and your skill set are satisfied, all is good.
Keep researching to improve your process, or just send your cases to DJ and let him form them for you and enjoy the shooting without all the work. Both are great options. I think that we often forget that having fun is the goal. Not everyone needs to be a world champion shooter to have fun.

 

[jjhall91]

Let your rifle tell you what works. If the neck is long enough to secure the bullet you are off to a good start. Depending on your chamber, you may have some issues with seating the bullet to your desired length, but if you, your rifle, and your skill set are satisfied, all is good.
Keep researching to improve your process, or just send your cases to DJ and let him form them for you and enjoy the shooting without all the work. Both are great options. I think that we often forget that having fun is the goal. Not everyone needs to be a world champion shooter to have fun.

Well said!

 

[jjhall91]

Jack,

My experience was sort of "coarse" so to speak. Started shooting dashers on a print specified 1.570", but it cut closer to 1.580". Had wonderful results on multiple barrels. After a few years I decided to get my own reamers, and was sure I was going to outsmart everyone else. I specified them for 1.555", and those all cut really close to exactly that. A couple years went by of struggling with multiple barrels. I then tried a br-dx for a while, and those were all 1.555". Again a couple years of struggling, although they would shoot small on occasion. I finally gave up on the cartridge, but also recognized the chamber length as a possible source of the consistency problems. Went back to 1.570" dashers, and shortly thereafter 1.570" BRA, been in the hunt for aggregate records ever since, whether I come up just short, or just barely beat them, the consistency is there. I wouldn't venture a guess as to where exactly length clearance becomes to little....best idea is it's somewhere between there and there lol. I tended to trim around 1.540" on my brass throughout all them years. With the exception of hydro formed dasher cases, which wound up down around 1.535"....and btw were clear to me my very best dasher years.

Tom

Sounds to me like you've got it figured out pretty good. I've been looking for a reason to get a new reamer. I think I'll try the 1.570 with a .269 neck instead of the 1.555 with a .2705 neck that I have now. In the meantime I'll have my FF barrel chamber opened to 1.570 and give that a try.

I'm going to resurrect my brass that's in the low.540s and and see how it shoots.

(I know exactly what you mean by("...somewhere between there and there...").

Thanks for the info, Tom.

Jack

 

[dogdude]

My shooting buddy ''wezz'', shot some of Mark Kings Dasher brass, 1.525. He produced a 3'' 1,000 yrd group.
1.570 chamber.

 

[jjhall91]

Not as good as some, but I do OK

Man! That's some pretty fine shooting!

 

[jjhall91]

My shooting buddy ''wezz'', shot some of Mark Kings Dasher brass, 1.525. He produced a 3'' 1,000 yrd group.
1.570 chamber.

That gives me some hope! I've got a "ton" of dasher brass in the 1.530s.

Do you know if he realized excessively bad carbon (especially the ring) or had short chamber life?

 

[LRPV]

My chambers measure 1.574” using the little steel plugs from Sinclair and an overly shortened case. Over the years I’ve used fire formed brass (Lapua blue box only) using a .257 neck up and slight crush fit false shoulder combined with a jammed bullet and it produced consistent length cases measuring 1.535-1.540” depending on the batch. I’ve also hydro formed my own brass first using a Hornady die and later a Benchsource die that again produces the same 1.535-1.540” depending on the batch. I have also bought hydroformed brass from Ryan Hunt (Hunt’s Longrange) and can you guess how long it was? You saw above what DJ had to say and I’d venture a guess that DJ has made more dasher brass than any one person in the world. I shoot IBS Benchrest 600 and a little 1k. I don’t always shoot a Dasher but when I do, I don’t do too bad. I won the 2016 600 Nationals, my LG was shooting my hydroformed brass +1 firing for most of the targets, the others were hydro +2. I shot THE Tackdriver last year (with my Dasher and 103 VT). I do some PRS type shooting with a dasher (poorly mind you). I’ve also shot my dasher at a mile and made contact where I intended. The consistency of your case lengths make a difference. The fact that they are shorter than 1.555” doesn’t mean shit and I am tired of hearing that it does. You can bang your head against the wall because O’Hara says you have to but there’s no need. I’ve said my peace now. I’ll go back to being quiet again but I hate to see anyone take misinformation as fact. More than one way to skin a cat.

 

[LRPV]

That gives me some hope! I've got a "ton" of dasher brass in the 1.530s.

Do you know if he realized excessively bad carbon (especially the ring) or had short chamber life?

Clean your barrels every 100 ish rounds and keep an eye on it and you won’t have a carbon ring problem in the chamber.

 

[johara1]

Thanks for the response. I will research.

Today, as a matter of fact, I had the most success, ever. I have a 100 yard range out back. I neck turned 10 Lapua brass to .0125. Used a .264 bushing to get .003 neck tension. Hard jam .030+-. (I was going to use 205 Fed primers, but forgot and used the CCI 450s.) I cleaned the chamber with brake cleaner and made sure the cases were absolutely clean.

I started with 30.0 grains of IMR 4064 (saving the H4895 and Varget)and increased by a .001 each load. By the time I got to 30.4 grains I realized 1.4855 length. Unfortunately, it started raining at that point.

Because there were zero signs of pressure, I'm going to try 30.5, tomorrow. I was thinking of "roughing" up the chamber a little to see what happens (FF barrel).

Jack

That is still a over .060 short, clean the chamber with non chlorinated brake cleaner and the fire form cases.... jim

 

[johara1]

Not as good as some, but I do OK

I guess for what you are doing you are fine. That is why in 1000 yard BR. you can't use electronic targets.... jim

 

[johara1]

IMO, to get to 1.570 AOL on a Dasher, it will thin the side walls each time you fire it in your chamber. The brass has to flow forward to get there. Depending on your chamber and condition of your chamber wall, is where the brass will grip upon firing and how much flows forward. Lapua brass comes out of the box approximately 1.555. Fire form it and it will be around 1.545 or hydro-form with 50,000 psi and it will form back to 1.535 to 1.540. Why would you ever want to buy a new reamer neck length 1.570? 1.570 provides more room for carbon rings.

There is plenty of neck at 1.540 to use provided you throat the reamer to maintain the bearing of the bullet at just above the neck shoulder junction. You will wear out the throat for the best accuracy duration of the barrel before you run out of neck to seat your bullet.

No need for a 1.570 chamber.

DJ
DJ's Brass Service
djsbrass.com
205-461-4680

A 1.570 chamber length was for the old Lapua brass.... the blue box bras we cut the length back to 1.560 10 years ago.... But knowing how to get 1.550 blow length ever time Keeps the cases uniform for volume. Granted it is hard to do and is one reason I went to the BR imp. great cases ever time...... jim

 

[Ccrider]

. The consistency of your case lengths make a difference.

You better believe this. In fact, wrote it in stone.

But knowing how to get 1.550 blow length ever time Keeps the cases uniform for volume.

See, both top shooters are telling us the same thing. And, other record holders have repeated this in numerous other threads. It’s the consistency and uniformity of the brass, not how long your case is (blow length) that matters.

Also, there is no carbon ring problem with shorter brass if you clean your barrel properly.

 

[jjhall91]

That is still a over .060 short, clean the chamber with non chlorinated brake cleaner and the fire form cases.... jim

Good morning! Thanks for pointing out my obvious error, Jim. My old age is showing more and more. The new length should not have read 1.4855. It should have read 1.5485. (As stated in the above post (#32-2nd paragraph) and after researching older posts. I did use non-chlorinated brake cleaner. It's from "Advance Auto" called "Weaver".) I did see a big difference when using the brake cleaner.

I went out, yesterday, and shot 5 loads of 30.5-4064. I was excited to see a 1.5510 on the first round, but then for some reason I had a low of 1.5475 and nothing equaling the 1.5510 after that. Go figure!

 

[jjhall91]

My chambers measure 1.574” using the little steel plugs from Sinclair and an overly shortened case. Over the years I’ve used fire formed brass (Lapua blue box only) using a .257 neck up and slight crush fit false shoulder combined with a jammed bullet and it produced consistent length cases measuring 1.535-1.540” depending on the batch. I’ve also hydro formed my own brass first using a Hornady die and later a Benchsource die that again produces the same 1.535-1.540” depending on the batch. I have also bought hydroformed brass from Ryan Hunt (Hunt’s Longrange) and can you guess how long it was? You saw above what DJ had to say and I’d venture a guess that DJ has made more dasher brass than any one person in the world. I shoot IBS Benchrest 600 and a little 1k. I don’t always shoot a Dasher but when I do, I don’t do too bad. I won the 2016 600 Nationals, my LG was shooting my hydroformed brass +1 firing for most of the targets, the others were hydro +2. I shot THE Tackdriver last year (with my Dasher and 103 VT). I do some PRS type shooting with a dasher (poorly mind you). I’ve also shot my dasher at a mile and made contact where I intended. The consistency of your case lengths make a difference. The fact that they are shorter than 1.555” doesn’t mean shit and I am tired of hearing that it does. You can bang your head against the wall because O’Hara says you have to but there’s no need. I’ve said my peace now. I’ll go back to being quiet again but I hate to see anyone take misinformation as fact. More than one way to skin a cat.

You have an opinion and I both appreciate and respect it. Further, the proven success you've had gives a great deal of validity to your claim. I would be foolish to argue against your (and other's) thought that consistency is the key and not necessarily length.

I began this thread to learn to find a way to increase case length as I felt the shorter length would contribute to more carbon build up and MIGHT impede accuracy. After hearing from several knowledgeable shooters I can now say that success speaks for itself and maximum case length does not appear to be a key factor in carbon prevention or accuracy.

This is not to say those who feel max case length is a key contributor to accuracy and less carbon have no point. It's simply to say my thought process has changed as I've learned a great deal from this thread.

Once again I thank you, and others, for the education I've been given.

Jack,

 

[jjhall91]

As my memory serves me the longer that I could make the neck the more free bore I could use which kept me out of the shoulder neck junction. The dreaded "Doughnut Area".

If nothing else, a very good argument for longer case necks!

 

[johara1]

Good morning! Thanks for pointing out my obvious error, Jim. My old age is showing more and more. The new length should not have read 1.4855. It should have read 1.5485. (As stated in the above post (#32-2nd paragraph) and after researching older posts. I did use non-chlorinated brake cleaner. It's from "Advance Auto" called "Weaver".) I did see a big difference when using the brake cleaner.

I went out, yesterday, and shot 5 loads of 30.5-4064. I was excited to see a 1.5510 on the first round, but then for some reason I had a low of 1.5475 and nothing equaling the 1.5510 after that. Go figure!

You may need to do a nice cross hatch with 320 in the chamber if it is too smooth. I used 220 with great success also.... jim

 

[jjhall91]

IMO, to get to 1.570 AOL on a Dasher, it will thin the side walls each time you fire it in your chamber. The brass has to flow forward to get there. Depending on your chamber and condition of your chamber wall, is where the brass will grip upon firing and how much flows forward. Lapua brass comes out of the box approximately 1.555. Fire form it and it will be around 1.545 or hydro-form with 50,000 psi and it will form back to 1.535 to 1.540. Why would you ever want to buy a new reamer neck length 1.570? 1.570 provides more room for carbon rings.

There is plenty of neck at 1.540 to use provided you throat the reamer to maintain the bearing of the bullet at just above the neck shoulder junction. You will wear out the throat for the best accuracy duration of the barrel before you run out of neck to seat your bullet.

No need for a 1.570 chamber.

DJ
DJ's Brass Service
djsbrass.com
205-461-4680

I was late responding to this post as, admittedly, it took me a while to fully grasp the situation (I'm no longer as sharp as I use to be) and research the criteria.

Everything you write makes sense and has impacted my thought process, much like LRVP and others. My emphasis will be on consistency in every facet. I will not rechamber nor will I devote excessive time and energy to the subject as I'm now convinced the need for longer cases is not as important as I once thought it was.

This takes nothing away from those who continue to strive for max case length as it is their belief. It's simply to say my thoughts in the matter have changed.

Thanks to all who took the time and patience to enlighten me!

Jack,