Hunter
Throwin' Up Spray
Wow, big changes possible there. If it's 32 at 9 and 62 at 3, that looks like about a 1.8 gr decrease. BTW, thanks for the information, and where can I get a copy of his treatise?
Anyone who says they can tell a difference when charges vary a tenth of a grain.
- Thread starter Louis.J
- Start date
Wow, big changes possible there. If it's 32 at 9 and 62 at 3, that looks like about a 1.8 gr decrease. BTW, thanks for the information, and where can I get a copy of his treatise?
Pete Wass
Well-known member
+1
There is no point in getting involved Reed. I have been debating this issue for about as long a I have been shooting and the answers are always the same. I do find it somewhat pleasing that more folks are weighing now.
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OK, in this light (I just caught up on the posts) I have three Borden short-range setups and 6 built by others. Maybe 15 shootable bbls.
I generally don't weigh my short range charges but I do shoot over the chrono a lot.
The Borden's are not picky nor do they go out of tune as quickly. "Out of tune" on a Borden is just a taller or crooked hole. I blame the builder for this.
Several of the others will go from bugholes to splatter. I blame the builders for this.
But in none of them could I find a tenth of a grain. First of all my throwers aren't that accurate, I work within .3gr increments at best.
I have no idea how wide the nodes are powder-wise because I use velocity as my guideline and my charge/velocity varies day to day. I haven't shot enough short-range competition to have any clue how to react in match conditions but at my range I generally go down because I'm generally working very near the top. If it all goes sideways and I can't get it back I drop the charges to my known "3250fps node" and start over. If this doesn't work I start looking at the gun.
I completely missed the sense of this thread.......... I've been mainly playing with other stuff than PPC lately
my bad
al
+1
There is no point in getting involved Reed. I have been debating this issue for about as long a I have been shooting and the answers are always the same. I do find it somewhat pleasing that more folks are weighing now.
Pete - You could take me up on my offer and settle this matter for all time.
IMO a lot of folks on the "Competition Benchrest" board only acknowledge "benchrest" at 100 and 200yds
I think that most 100 / 200 yds Benchrest shooters on these forums acknowledge that with internal ballistics, using generalizations does not work. Because of that most are careful where they resource information. Here is a quote from a credible source: “In shooting tests it has been discovered that a less than +/- 1% variation in the powder charge has no significant influence on accuracy.” (VihtaVuori) They also say that powder temperature and moisture content are factors affecting accuracy.
Ken
And why is this credible? "Significant" is relative. At 1000 yds 5fps has a measurable effect. "Measurable" is significant, and +/- 1% is HUGE! Depending on the case it can easily mean 50 or even 75fps.......50 or 75fps will put you in "foot tall" category at 1K. Shucks, anything over 50fps and you'll be scratching at 100yds!. Even shortrangers try to keep ES under 40fps.
Vihtavouri has never won a 1K Bench Rest Match
Anywhere.
al
Kevin,
The difference I am talking about is calculated from a curve fit of a ladder test over several grains of charge difference. Over this large interval, there are several steps in the ladder where the changes in elevation are small, but also some spots where the changes are larger. On average, the change is 0.010" per 0.1 grain. I expect any BR rifle would do something similar.
Cheers,
Keith
Like I say you can not generalize; 100/200 yds. is not 1K and similarities are few. As to credibility, I am not sure how many group shoots you have been to but throwing is the norm; and I have no doubt of VihtaVuori’s testing. If you re-read the quote, you will see that they say with a less than +/- 1% variation. You said yourself you generally don’t weigh for short range: “I work within .3gr increments at best.”
We were talking 100/200 yds. right.
Burn rate, case capacity, sectional density, expansion ratio and barrel length are just a few of the variables. The effective work performed in a long barrel and a relatively slow burn rate powder and one in a short barrel with a faster burn rate is different. Small differences in charge weight will show more in a rifle where the gasification rate produces a pressure travel curve that is lower in pressure and longer in travel rather than one that does its work with a quick rise high peak pressure over a shorter travel.
Ken
Pete Wass
Well-known member
I have Aviation Fobia Wilbur
I would have to drive. I visited Gene Beggs a few years ago and he gracously allowed me to use his stuff and shoot in his Shooting Facility. I believe, if there is any place that all of this can be proven, it is there. I think I remember Gene as being in the Throwing Camp. I would like to go there again and try to prove what I see when I test loads at my home range. Now perhaps, 6 PPC have broader tuning bands than the 30's I'm use to, I don't know but all the 30's I've ever shot had distinct, very narrow, "Nodes", if you will, where they shot at their very best. I have only ever been able to do it with exact loads and exact seating depths.
I would have to drive. I visited Gene Beggs a few years ago and he gracously allowed me to use his stuff and shoot in his Shooting Facility. I believe, if there is any place that all of this can be proven, it is there. I think I remember Gene as being in the Throwing Camp. I would like to go there again and try to prove what I see when I test loads at my home range. Now perhaps, 6 PPC have broader tuning bands than the 30's I'm use to, I don't know but all the 30's I've ever shot had distinct, very narrow, "Nodes", if you will, where they shot at their very best. I have only ever been able to do it with exact loads and exact seating depths.
sez who?
It doesn't matter on several levels.
There's no discussion of whether or not "exactness" is detrimental. The discussion, as I see it, is about the effort involved with exactness - whether or not it's wasted effort. I don't think it's worthwhile shooting group benchrest but can't argue the point because of the "can't hurt" card. The only way exactness could be detrimental is thinking that your rifle will be competitive if the loads are exact, hold is exact, trigger pull is exact..etc...
I used to be scared to death of airplanes. Still am when it comes to landing but I've always flown (when I could buy a ticket) rather than sit in a car for hours on. Lived a year of terror in Vietnam where we went everywhere in helicopters with no doors.
Do not know if i can post in here, but here we go!
Anyone Give this question a honest answer.
Best one i have read for a while. Thanks Boyd!
Regards
Jim
Here's a dreamer who's in the Benchrest Hall of Fame. Unless I'm wrong, that leaves everyone out whose responded so far.
Load Tuning by Speedy Gonzalez
“Find the Sweet Spot--A load that is too light or too heavy can cause vertical problems. When you've tuned the load right, you should see a reduction in vertical. Even 0.1 grain may make a difference, as will small changes in seating depth.”
“For his .263″-necked brass, Speedy Gonzalez has a full set of carbide neck bushings, in .0005″ increments from .256″ to .261″.
“He also has four different body-sizing dies, which allow him to choose the exact amount of sizing he wants, both at the shoulder and at the web. Most of us can’t afford such a collection of dies, so you want to start with a good basic full-length die that brings in the shoulder a little less than one-thousandth."
Source: www.accurateshooter.com
Now THIS is the mark of a guy who has actually BTDT AND MADE IT WORK!!
Not my way, but A WAY, and recognition of the problem.
Good On Ya Speedster!!!
al
Regardless of factors (wind) producing large errors, sources (0.1 powder charge) of small errors still cause errors. For every match, there are at least a couple of shots that I wish were 0.010" closer to the dot, and some that I am glad weren't 0.010" farther from the dot. Everything matters.
Cheers,
Keith
Jim Borden tells the story of how his dad won a match using ammo from the wrong gun. He grabbed loaded rounds for the wrong rifle, loads which were not properly tuned.
He won the match. But Jim was peeved.
His dad said "but I WON!"
And Jim said "so what, you could have set a record!"
Screw "the wind." The wind IS..... but why give it more points?
al
He won the match. But Jim was peeved.
His dad said "but I WON!"
And Jim said "so what, you could have set a record!"
Screw "the wind." The wind IS..... but why give it more points?
al
V
VT52
Guest
Average Joe will not see a difference in 0.1gr changes. I think you have to be shooting at the edge to see these kinds of effects. Competitive BR, long ranges. If you're playing a half minute game, then it will not matter one bit.