Fire forming for a Dasher

[L-46]

I use 115 Bergers for fire forming and i also use 108's , Varget and fed primers. Cleaned chamber and cases with non chlorinated brake cleaner and don't let them get hot……. jim

Jim
Do you think it's the 115 & 108 bullets helping with achieving the lengths you are getting?
Or just a combination with the dry chamber?
Richard

I think it is the clean/dry chamber and the heavier projectiles,
some tests i did with 65gn and a similar pressure dry load gave me shorter cases than the 80gns pills.
I will have to stick with the 80's now as i have done 1/4 of my cases trying to figure this out.

Jim, are there any advantages in the longer case?
looks like i will be trimming at 1.535"

 

[johara1]

I have no idea how long your chamber is……. 1.570 was the old length mine is 1.560+- a few thousands. Say yours is 1.570 and your case is 1.535 thats .035 gap for carbon to build up. The short neck on the Dasher doesn't need to be any shorter, does it hurt accuracy ……. yes…….. jim

 

[4xforfun]

I have no idea how long your chamber is……. 1.570 was the old length mine is 1.560+- a few thousands. Say yours is 1.570 and your case is 1.535 thats .035 gap for carbon to build up. The short neck on the Dasher doesn't need to be any shorter, does it hurt accuracy ……. yes…….. jim

I gotta disagree a little bit. I accedently trimmed my brass WAY, WAY, WAY short when preparing for the IBS 1K nationals in 2011. That brass has always shot very well since.

My thought...consistancy in length is more important than how long.

Just my .02.

 

[Raythemanroe]

Until you get that carbon ring.



Ray

 

[Gennaro64]

DON'T LET THE "CARBON BUILD UP" "CLEAN IT EVERY TIME" "NO PROBLEM" NO MATTER WHAT YOUR REASONABLE TRIM LENGTH IS. just my opinion.....

 

[johara1]

I trim .014 short of my chamber length, so i have .014 of carbon to clean. With a neck only one cal. long i don't want to give up any more neck than i have to……… jim

 

[4xforfun]

DON'T LET THE "CARBON BUILD UP" "CLEAN IT EVERY TIME" "NO PROBLEM" NO MATTER WHAT YOUR REASONABLE TRIM LENGTH IS. just my opinion.....

Exactly!! And, I never have had the carbon ring problem. Whenever I have accuracy issues, I always have some guy standing around with a bore scope saying "I'll show you why...it's a carbon ring." Five min later they retract their carbon ring statement...because it's not there!!!.

Maybe I'm just licky!!

 

[dmoran]

Exactly!! And, I never have had the carbon ring problem. Whenever I have accuracy issues, I always have some guy standing around with a bore scope saying "I'll show you why...it's a carbon ring." Five min later they retract their carbon ring statement...because it's not there!!!.

Maybe I'm just licky!!

Must be talking about more recent times......
Back a few years, I remember seeing and cleaning out dominate carbon in one of your barrels.

DON'T LET THE "CARBON BUILD UP" "CLEAN IT EVERY TIME" "NO PROBLEM" NO MATTER WHAT YOUR REASONABLE TRIM LENGTH IS. just my opinion.....

+++1.... exactly

 

[4xforfun]

Exactly!! And, I never have had the carbon ring problem. Whenever I have accuracy issues, I always have some guy standing around with a bore scope saying "I'll show you why...it's a carbon ring." Five min later they retract their carbon ring statement...because it's not there!!!.

Maybe I'm just licky!!

Must be talking about more recent times......
Back a few years, I remember seeing and cleaning out dominate carbon in one of your barrels.

DON'T LET THE "CARBON BUILD UP" "CLEAN IT EVERY TIME" "NO PROBLEM" NO MATTER WHAT YOUR REASONABLE TRIM LENGTH IS. just my opinion.....

+++1.... exactly

Yep..and I learned my lesson. I remember not even knowing what you meant by carbon ring. Many 1000's of rounds later and I'm ring free. I may end up with accuracy problems, but they are either loading bench issues or shooting bench issues (ie...poor technique).

 

[4xforfun]

I do have a question about the carbon ring. As we all know, factory chambers are usually very generious in dimensions, and factory ammo is usually very much the other way. So my questions is...whay havn't we ever heard of a carbon ring on a 270...7mmxyz....25-06....223...ect...? Or how about match chambered 300 WSMs or strait 6mm BR's and 6.5-284's.

What makes the ring a dasher thing? Why doesn't anyone have the problem with their other chambers? Untill the dasher became popular, I had never even heard of the problem.

Just curious.

Tod

 

[dkhunt14]

I would imagine the Dasher is subject to it because of the short neck and guys trimming and forming way shorter then the chamber length. Matt

 

[4xforfun]

Maybe, but the 300 win has a short neck..the 7mm rem mag, as do a few others. And we know that the factory chambers are generally chambered long. And with most cases, the reloading manuals say to trim .020 shorter than PUBLISHED MAX, and we know that factory chambers are usually longer than that. My bet is that with brass trimmed per min specs there could be at least .050 clearence. That is more than most guys run their dashers. That is plenty of room for a ring to factor in.

 

[dkhunt14]

Yeah but none of the mentioned have a 40 degree shoulder directing things to the outside. The turbulence point. They act more like a funnel and direct forward. Even the Win isn't as short as a Dasher. I would bet the trim length on factory isn't much forward of SAMMI. Its the rest that has extra room including the freebore. My loading manuals say to trim no more then 10 less. Matt

 

[dkhunt14]

I have noticed my buddy's Dasher gets the carbon in the neck area and mine doesn't. He uses one of those bore guides with a tapered rubber piece on the end. I believe he doesn't get cleaning fluid soaking in the neck area. I use a Sinclair with an o-ring and I get cleaning fluid plus the patch opens up and goes through the neck area. I believe this helps keep the area clean. We both soak our guns between matches. Matt

 

[dmoran]

Tod -

Over the years I have seen dominate carbon and carbon rings in 6BR, 6BR Imp, 243, 243-AI, 260, 6.5x284, 7WM, 7RUM, 300WSM, 300WM, 300RUM. There may have been more but those are the ones I am remembering.
It is to my experience, "ran over carbon layer" is the number 1 killer of a barrel (particularly of the throat).
The best calibers I've seen that carbon the least are 222, 223, 6PPC, and 308.
D

 

[4xforfun]

Tod -

Over the years I have seen dominate carbon and carbon rings in 6BR, 6BR Imp, 243, 243-AI, 260, 6.5x284, 7WM, 7RUM, 300WSM, 300WM, 300RUM. There may have been more but those are the ones I am remembering.
It is to my experience, "ran over carbon layer" is the number 1 killer of a barrel (particularly of the throat).
The best calibers I've seen that carbon the least are 222, 223, 6PPC, and 308.
D

Would the ring clean up on those you mentioned? Could they be brought back to life with a good scrubbing? How about a BBL setback..would/could that revive them?

Honestly, this is the first mention of a carbon ring problem out side of a dasher that I have ever heard. Learn something new every day!!

 

[KWeigel]

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