6 Dasher - .020" Jump???

[CaptainMal]

This is my potential dog stake. Worst shooting gun I own ... until today.

Literally an OVER MOA rifle. I took it back to the builder and he found nothing wrong. Then he told me to jump the 107 Sierra's .010 or more. Reluctantly, I tried that today, loading .010" and some .012" off the lands.

He also told me to watch the measurements. Said the throat would move out maybe .004" or more the first couple hundred rounds.

Turned out my throat had moved out .007" in just 200 rounds. The now .017" still
shot horrible. The .019" shot "bugeyes" and the first time I ever got groups from the gun.

Why? Why the throat change and why so much jump to shoot?

 

[drybean]

can not anserer your ?
but whos stock is that

 

[CaptainMal]

That stock was hand-made by Eric Bostrom. He lives near Myakka City, Florida. A cabinet maker by trade, he buys raw strips of different woods, slices, dices, glues, presses and shapes them in a garage behind his house.

Was told it was modeled after some factory stock. Don't have a clue and never asked.

 

[brxbrad]

I have a BRX with a savage action , I shoot 105 VLD's and load development took me from .010 into the lands to .040 off. My groups come together at .030 off the lands. Now it shoots like a laser. Don't give up on it. The throat erosion seems a little excessive though.

It is what it is.

Sorry I cant help you more.

 

[CaptainMal]

.030" off the lands... WOW!

Local fellow also has a BRX. Sierra's .008 off for him.

Heard Berger's liked it engaged or close. Thanks for the information. Just that little bit tells me it's not all that unusual to be so far out. Appreciate the response.

 

[TerryPohl]

Some will shoot in the lands and others out of the lands. It is just like a powder type, each gun is unique in that manner. If you do a search Erick with Berger put out an article on how to find the sweet spot for your gun. My custom 300 Win. Mag shoots the 185 VLD's with .150 off the lands believe it are not.
Terry Pohl

 

[brxbrad]

Here is the link for Berger tech info. VLD info is at the bottom of the page..
http://www.bergerbullets.com/Information/Tech%20Info.html

 

[CaptainMal]

Another thanks is due. Never would believe that info. about Bergers unless you pointed out the link.

I'm using Sierra's right now and will do more seating-depth testing with more confidence next week.

 

[niceone]

my 6br likes 20- 30 jump

 

[keithcatfish]

When I began load development for my McGowan barrelled Savage 6BR with 95 VLDs, I started .030 off the lands. Since I hunt with my rifle, I didn't want to deal with jammed bullets in the field. The worst group was .42 at 100 yards, the best .22. Load development complete at 31 g of Varget...

I may catch a lot of heat for this, but unless you are shooting short range benchrest where a couple hundredths of an inch mean the difference between tenth and first, I think jamming bullets is way overrated.

 

[jhord]

Take this as input from an idiot, but... I think sometimes when the barrel is chambered there might be a bit of a burr or something left on one of more of the lands. When you initially find your seating depth to the lands, you are maybe hitting a burr and getting a false reading. I recently worked with a new rifle that was like this. The bullet would feel "sticky" at the lands and readings were inconsistent. After 20 or so rounds down the tube, things smoothed out and the throat gained about .005" or so. The readings became much more consistent and the bullet felt "square" and positive when it hit the lands.

As far as the Sierra 107's go, in my 6BR I am jumping them .020" at this time. I am jumping Sierra's .100"+ in my .308 depending on the bullet version. In the rifle mentioned up above, a .223", I messed around in a range from about +.015" to -.020" and got nowhere with any bullet. Then I shot some rounds that were set up to magazine feed, I don't know the exact jump but its huge... and it started shooting bugholes. Lesson learned, don't be afraid to make massive changes in jump.

 

[CaptainMal]

JHORD.

Your response is so thoughtful and informative. I made a small contribution to this forum because of earlier comments and value I received. Not credited yet but that will come. Looks like I will have to make another.

That mention of why I may have had an earlier false reading is somthing I thought of. I did have some diffent readings then, which I attributed to inexperience using the Hornady tool. Today the readings are very repeatable and the bullets easily tap out after the reading is taken.

Could be ...could be.

 

[jhord]

Thank you for the kind words, but I'm just passin' along stuff I have learned from here and a little bit of what I have seen for myself. Yes, it is a great forum. The part I quoted below is EXACTLY what I'm talking about. I have the Hornady tool too. That's a great looking rifle you have, my 6BR is Savage-actioned as well.

JHORD.

Today the readings are very repeatable and the bullets easily tap out after the reading is taken.

 

[CaptainMal]

FYI...

Nothing I did worked. Gonna turn it into a dog stake, or should I say steak?

It's sad when the fireform loads shoot better than anything else. It's barely an MOA gun. I gave up today.

 

[brxbrad]

I wouldn't give up yet.......If it where my gun, I would take it to my smith and have him scope the barrel and basically give it the once over. I trust my smith completely so based on his opinion, I would make my decision from there. Maybe it just throat erosion, maybe the barrel is shot out. You never know.......2 cents

Good Luck

 

[CaptainMal]

Came to an awful realization today. Made a fool of myself with this gun. Builder was there. Gun would not shoot. Another fellow loaned me some of his loaded Dasher to try. I measured and said - "NO"! It would be jammed over .050".

Builder discovered my measuring was that far off and more. I was using a 6 BR case on the Hornady/Stony Pt. tool. Can't buy a Dasher drilled case so I figured...

What a fool I am. Lucky I didn't hurt myself fire-forming as I was not even touching and thinking I was jamming .030". Tested with jumps over .070" because of my stupidity.

Builder is making me a Dasher case to properly measure. Been thinking I'm as dumb as I look. Maybe I should NOT be in this game? Making such a serious mistake and repeating it for months, is unexcusable.

Gun probably does shoot decent. Other ammo showed promise. Now I either give up on the target game or start from scratch.

 

[TheBlueEyedBear]

It is an embarassing proposition to admit to these "imperfections" in reloading. That's why you don't read too many of them. Most of us have had them (Isure have!). I guess that's what they call learning. Thanks for sharing your experiences. You may have just saved someone else from doing that down the road. Or, time will go by and then someone will do the same thing. Fortunately we sneak by and learn a little more each time. Fortunately those SAAMI specs have some protection built in.

 

[wildchild]

Thats nothin...I was partly responsable for a 308 win going off in a 270win...

 

[jhord]

I loaded 3 rounds of .223 the other day before I realized I hadn't primed the cases yet. "Where are these grains of powder coming from?" Doh.

Anyway, glad you got to the root of the problem. That's a beautiful rifle, I bet she'll shoot fine...

 

[Forum Boss]

It's not uncommon to see some gross errors initially when guys start using the Hornady (formerly Stoney Point tool). Three guys I regularly shoot with were way off for a variety of reasons:

1) not having a proper sample case that fit their chamber
2) not ensuring the shoulder of the sample case butts up firmly against the chamber
3) allowing bullet to be an a slight angle then pushing too hard.
4) pushing real hard.

What you want to do with the tool is ensure the sample case is firmly seated in the chamber, with about 30% of the bullet exposed. Then push the rod very slowly and gently forward. When you feel the first resistance STOP. Now give the end of the rod 2-3 gentle taps. Sometimes the bullet will jump forward, indicating it wasn't truly in the throat.

Using this technique I can generally repeat measurements within .0015 very consistently. The last time I showed this method to a guy we found that he thought he was .010" in the lands and he was actually about .040" off initial contact. He ended up getting best accuracy when he moved his bullets to a true .010" past initial contact. Using the gentle, slow push then light tapping technique, he was able to get repeatable readings thereafter.

One of the posters is absolutely correct that in the first 30-60 rounds there may be a high point or burr on one of the lands. When that finally smooths out, it is not uncommon to be able to move the bullet in a lot farther--as much as .015. But then it stabilizes.

With a clean chamber you should practice with the tool until you can get consistent repeat readings with the same bullet.