Lou Murdica's process

[marchx]

Depends on what you call accuracy. At major short range BR events they are trying to shoot 25 shot aggregates under 0.200".

0.2-.04 for a 10 shot group.

 

[geo.ulrich]

Erik Cortina made the comment in his "Chasing the lands is stupid" video, that seating depth can tune any load. However, he does state that this may not be the best or most accurate load.

Isn't this kind of a contradiction of terms. " you can use seating to tune any load , but it may not be the most accurate " then the gun isn't in tune ./....

 

[BoydAllen]

Isn't this kind of a contradiction of terms. " you can use seating to tune any load , but it may not be the most accurate " then the gun isn't in tune ./....

I think that he meant that you can see variations in accuracy by changing seating depth, no mater what the powder charge, but the best of those variations may not give the accuracy of a load with the optimal powder charge. Back in the day, I discovered that the effect of seating depth is very large, but of course powder charge is also important. It is not one or the other. It takes both.

 

[Bill Norris]

Isn't this kind of a contradiction of terms. " you can use seating to tune any load , but it may not be the most accurate " then the gun isn't in tune ./....

I think he could have meant that the tuned load may not be the most accurate load as far as bullet, powder, powder weight, neck tension, and seating depth as a whole meaning try another complete load.

 

[geo.ulrich]

O.K. I'll say it again if its not the most accurate load then the gun isn't in tune... nobodies going to matches after FULLY tuning there guns lets just say to shoot .180 groups and then changing to get it to shoot .250 groups .... I can't actually believe its a youtube video , hell its in every reloading manual I own from the 60's on into to the lands raises pressure off the the lands reduces pressure. as Boyd said there is more to the puzzle its just one piece...

 

[gunsandgunsmithing]

O.K. I'll say it again if its not the most accurate load then the gun isn't in tune... nobodies going to matches after FULLY tuning there guns lets just say to shoot .180 groups and then changing to get it to shoot .250 groups .... I can't actually believe its a youtube video , hell its in every reloading manual I own from the 60's on into to the lands raises pressure off the the lands reduces pressure. as Boyd said there is more to the puzzle its just one piece...

I don't disagree George. But the way I read it is that changing seating depth may well help tune to that load's "potential" in that gun and in a given condition. Just like tuning to the potential of a given bullet, but changing bullets and it dots right up. Ultimately, if it's not dotting small, it's not tuned to the guns potential. Assuming the gun can shoot, of course.

 

[geo.ulrich]

Mike, I agree with that ," the given bullet" to a point all else would need to be equal ie. the same jackets used ...

 

[gunsandgunsmithing]

Mike, I agree with that ," the given bullet" to a point all else would need to be equal ie. the same jackets used ...

Usually, a proven great bullet will shoot, but not always, in every barrel. Ultimately, don't force the gun to shoot something it doesn't like, no matter the quality of the bullet. I wouldn't care if blems shot in the zero's and a premium custom didn't...I'll go with what aggs best.

 

[geo.ulrich]

The key words there are " a proven good bullet" there is a reason why bulletmaker x has the greatest one year and someone else has the best the next year. bullet maker x didn't forget how to make bullets his lot of great jackets is gone and now the next one has the good lot...the one that has it figured out over the good and the not so good lots over the years is the real bulletmaker .... and I can only think of two that can do that at this time ....

 

[DaveTooley]

When I reached max workable pressures with the bullet touching I would seat the bullet deeper .005" at a time. I shoot at 200 yds. If the rifle started showing vertical I would increase the powder charge to flatten out the group. I also wanted to find the limits or how wide the sweet spot was. Once I found that I would determine powder charged based on the season. Late spring I would be on the lower end of powder charge so I could shoot the same load load on into the summer before having to reduce the charge and retest.
I've built myself three 280 Ackley's over the years. I wanted to shoot a 150 gr. bullet. Never happened. Use a 140 and they all shot great. Go figure. Every group you shoot is telling you something.

 

[CNC-Dude]

I think he could have meant that the tuned load may not be the most accurate load as far as bullet, powder, powder weight, neck tension, and seating depth as a whole meaning try another complete load.

That's kinda what I understood his comment in his video to mean.

 

[gunsandgunsmithing]

The key words there are " a proven good bullet" there is a reason why bulletmaker x has the greatest one year and someone else has the best the next year. bullet maker x didn't forget how to make bullets his lot of great jackets is gone and now the next one has the good lot...the one that has it figured out over the good and the not so good lots over the years is the real bulletmaker .... and I can only think of two that can do that at this time ....

Yessir! I agree 100%! Bullet making is almost voodoo but it's not! Every little thing can matter and every lot of jackets can make a bullet maker a hero or a zero! The good ones know what to look for and how to adjust for it. Bullet making is something you have to commit to being good at. I'm not saying I am..to the contrary. But I made enough to see that you have to keep up with everything and learn how to make the proper adjustments as needed.

 

[1shot]

I've used the same basic process for 30 years when tuning up a rifle regardless of the intended purpose. I go to the range with one powder and 3 or 4 different bullets. Powder has NEVER made a poor shooting rifle perform better. Powder has NEVER improved the marriage between the barrel and bullet. I know in short order which bullet/s the rifle likes. I start with each bullet touching the lands and go up on the powder charge until I see pressure signs on the brass. That's the worst case for generating pressure. I shoot two shot groups with seating depth changes. If that bullet doesn't show me anything I move on. When I find something that performs well I'll shot 3 shot groups if it's a hunting rifle and several, more than 3, 5 shot groups if it's a target rifle to confirm. An afternoon at the range and I'm done.

This post isn't meant to start a whizzing contest, but there are exceptions to every rule I have found out. On several occasions I have found that using a bullet that the barrel likes, a powder change can make the rifle go from bugholes to patterns. One would ask, if you have a great load, why go searching for something else? In my latest experience, I couldn't get the powder I wanted, so finding a suitable replacement was forced upon me. I knew that powder "A" was a proven winner paired with the bullet of choice for that barrel, so the search was on. After testing several powders with no good result, I switched bullets, and found a load that worked as well as my original load fairly quickly.
So, I guess a person could say that certain bullet/powder combinations work better than others combinations. Keeping with other posts, I'm a sling shooter, but load like a long range BR shooter.
I hope this helps,

Lloyd

 

[VA_XTC_Shooter]

Very interesting. My 'accuracy' shooting is done from prone with a sling - 1/2 - 3/4 MOA is great for what I need.
Can I really choose an arbitrary velocity and tune with seating depth to get that type of accuracy?
Currently, I'm using GRT to pick a starting load and, then, if that load isn't sufficient, do a 'ladder' above and below.
Thanks!

For us sling shooters, One thing I knew in the back of my mind is what is my hold ability with the sling. The only way I can measure this is with a SCATT. I at least know what the smallest area my hold is and know I can’t expect a group smaller than that, in reality it will be larger.

 

[jelenko]

For us sling shooters, One thing I knew in the back of my mind is what is my hold ability with the sling. The only way I can measure this is with a SCATT. I at least know what the smallest area my hold is and know I can’t expect a group smaller than that, in reality it will be larger.

Good point. I can see my wobble with a 1/2 MOA dot and 18X mag. On good days [i.e., not hot], the dot wobbles back and forth between the inside of the X ring on an MR31 at 100 yards. With the X ring .8 MOA and the dot .5 MOA, I've estimated the wobble at ~ .3 MOA.
My challenge is not over hold when shooting for group size.

 

[Alex Wheeler]

I build and tune everything from Benchrest to sporter hunting rifles and heavy ELR rifles. Theres a lot of differences between the different types of rifles. They do not all respond to similar tunes. While some bullets and powders shoot best in the lands, others will not for example. We do sometimes get a bit short sighted in the tuning world, Br cartridges do act quite a bit differently than your standard round. I am only posting this to encourage people to explore things that are not "common" loading techniques. We have learned a bunch from newer shooters doing just that.

 

[INTJ]

Whenever we start taking about BR vs everything else, its important to remember that short range benchrest is very different than long range benchrest. SR BR is loading at the range while shooting, LRBR is loading before the match, hopefully in conditions that are as close to match conditions as possible.

There are a lot of LR BR methods that work well for any long range shooting discipline. There are some LRBR methods that are unnecessary or a bad idea in other disciplines. In a 6 BRA we can legitimately see changes with .1 grain increments, and in the 300 WSM/300 SAUM IMP .2 grains makes a noticeable difference. I would never make that fine of a change in a hunting rifle in those cartridges.

In hunting rifles I make larger changes and want wider nodes. I am happy with a lot less accuracy as well. If my "timber use" big hunting rifle will shoot consistent 6" three-shot groups at 600 yds, I am happy. If my LR BR LG shoots consistent 6" 5-shot groups at 1000 yds the barrel is coming off.

 

[garandman]

@BoydAllen .... VERY helpful. Thx.

 

[1kbrxDave]

I build and tune everything from Benchrest to sporter hunting rifles and heavy ELR rifles. Theres a lot of differences between the different types of rifles. They do not all respond to similar tunes. While some bullets and powders shoot best in the lands, others will not for example. We do sometimes get a bit short sighted in the tuning world, Br cartridges do act quite a bit differently than your standard round. I am only posting this to encourage people to explore things that are not "common" loading techniques. We have learned a bunch from newer shooters doing just that.

You never know where a better idea will come from-----or lead to.

 

[searcher]

I came across this article

Top Benchrest Shooter Lou Murdica Talks With LoadDevelopment.com - LoadDevelopment.com

To get to the real world truth about precision rifle reloading, we talk with pro shooter Lou Murdica.

www.loaddevelopment.com

I find it very informative. What does he mean "Don’t over size your brass."?
What do you think about his load development process:

1. I work up my load using a powder that fills the case.
2. I start with bullet making almost a square mark from the lands of the barrel
3. Then I load the powder on the light side and shoot 2 shot groups working up in powder 1/2 grain at a time until I start to see pressure signs.
4. Then I look at the 2 shoot groups and shoot 3 shot groups of the loads that look good.
5. Then I shoot 5 shot groups again from those that look good.
6. I take the best group and then back off the lands .003 at a time and see if it can improve groups."

I don't quite understand why he is doing no. 4&5 with a bullet in the lands. Isn't that too risky? Why doesn't he start at at least t thau off?
I cannot seat bullets to exactly the same length I always have 1-2 thau variation. If I seat the bullets 0-5 thau off the lands does this 2 thau variation in CBTO has bigger impact on velocity (pressure differences) than if I seated my bullets 10-20 thau off the lands?
I am looking at 100m-300m accuracy.

Mr Murdica's procedure is pretty much the same as a lot of bench rest folks use, I think. My procedure is almost the same. You ask why not start .003" or so off the lands. First - his reference to using powder that fills the case is not to be interpreted as starting high on a ladder test. He is just trying to use a powder that most fills the case when load is developed as opposed to one which leaves a large powder void in the case - which many powder options will do - even at max safe operating velocities. The void will create erratic velocity. I'm, guessing he chooses to shoot "jammed" as opposed to off the lands for a few reasons. First in my mind is shooting jammed eliminates much bullet "damage" from the bullet otherwise hitting the lands slightly off-center due to concentricity issues or "slop". While some loads just don't like being jammed - it is not lost on most shooters that a lot of loads love it above all else- be it because it tightened up concentricity or because of other dynamics which made it the better load in that rifle. About 75% of my target barrels prefer a jammed load with the load I shoot in them. Maybe that is because I automatically go to jam as Mr. Murdica does and that enables me to see that the benefits of jamming are consistent enough to go there first - whereas someone who always starts well off the lands and never feels comfortable jamming just picks the best setting he came across. It is assumed by Mr. Murdica a REDUCED load is used initially, I'm sure. But a newcomer might interpret what you stated as just starting off jamming a bullet with a full case of powder. Not something any of us ever wants to do. You will encounter, as you say, velocity differences when seating bullets at different seating depths - but anytime a major seating depth change is made, an initial reduction in powder is warranted - especially when seating much deeper or going jammed..