Adventures in Production Class

Today was a long day at the range wringing out the Marauder. (Yes, I do deserve that bottle of wonderful Oregon Pinot Noir tonight! :))

Steve, I did try different positions on the front bag and found that having the back of the ear on the bag about 9" into the stock made a significant improvement in groups. Thanks for that tip! I have also learned that the gun prefers a very light touch.

As far as pellets are concerned, I am down to 4 pellets, two brands - Air Arms and JSB both heavy & light.

I am coming to the conclusion that I need to start tweaking velocities to see if that brings any pellet to the forefront!

Again, thanks for all the encouragement!

Steve W.
 
I have a Benchmark barrel on the kid's marauder now. I also put a new reg that is very consistent. He kicked my butt today benchresting in the basement.
Dan

Wayne Burns said:
Steve,

I think my comment might have been misunderstood... I'm not saying there is a glass ceiling on your marauder. I'm suggesting that the out of the box Marauder, seems to have limit of about 700 score for three cards... based on the testing so far. Our club members report that the transfer port on the ones we looked at so far have burrs which damage pellet skirts... which produce flyers that "fly" further into low point land. Lead fowling can do this also to otherwise wonderful barrels.

I guess "Production" Class won't allow one to clean up that burr, since it's not in the "Owners instructions". I believe the Marauder can shoot in 740s... and why not 750 with a reg and super barrel, (some crosman barrels seem great too after the deburring) the trigger can really get great with adjustments only, plenty of very stable shots with a reg, 750 seems all very possible.. Mark and Bob are working on that project now. So is Dan Brown.. and others I'm sure.. the gun has promise!

Bottom line I'm saying is: For a newbie to benchrest, with an out of the box Marauder... you're doing super! Keep up the quest! But keep in mind that searching for the best pellet and or technique, really can't begin until you quit damaging the pellets before they get a chance to preform... maybe

Wacky Wayne
Click to expand...
 
Dan,
Thanks for the report... I love it.. what a great base to start tweaking with.. the Marauder is good out of the box and can really contend with some work..
Thanks for sharing all your trials and testing info Dan!

Wacky Wayne
 
I was talking to the kid today to see what changes he would like with his gun. I thought he would like some trigger work but he is happy with the current adjustments with the stock trigger. We may make a new brass trigger blade.
I may change the barrel thimble with one that has the oring mounted on the bolt. That will ease the entry of the pellet some.
Now the kid needs to practice standing and kneeling shots so that he can defend his title properly this year.
Dan
 
Steve,

Glad to hear a change in position helped. Another idea to help bags form a little better, without the use of a mallet, a little water or spray starch on a bag, gun goes in, pressed down and left outside in the sun to dry. Ask Ron about Levis. Good luck.
 
Steve, I reminded Ron that the cowboys of old would wear their Levis into a stock watering tank & then let them dry while wearing them. :)

I'll wait until we have warm summer weather to do this. I will also use plastic wrap on the stock to keep it from getting wet. Good idea - thanks for it.

Steve W.
(Off to shoot pistol field target with Wacky Wayne this AM)
 
Our next benchrest match is this coming Wednesday, and I wanted to spend some time tweaking my Marauder prior to that. Thus, I convinced Ron to join me at the indoor range with his chronograph. I was hoping to determine a good, accurate velocity that would increase my scores, find the power curve, hone in on the proper pellet, and continue to improve my understanding of the rifle and its likes and dislikes. Pellets selected were Air Arms Diabolo Field Heavy and JSB Diabolo Heavy.

The initial factory velocity setting was 870 fps. I felt this was way too fast, and I adjusted the hammer spring preload and hammer stroke to produce an initial velocity of 771 fps on a fill of 2400 PSI (using the Marauder gauge which I know to read about 200 PSI low). After 12 shots the velocity had increased to 783 fps. Another three and it was 786 fps. Another 3 and velocity stabilized at 788 fps. Reading on the pressure gauge was 2250 PSI. Continuing through the power curve, and velocity remained in the 800 to 806 fps range for 36 shots total. Velocity then dropped off dramatically for the next 12 shots ending at 779 fps where we stopped.

Analyzing the data, the power curve was at its peak from 2250 PSI through about 1900 PSI (we did not actually record that pressure but interpolated based on a pressure reading of 1800 PSI 6 shots after the power curve started to drop.

Pondering this data, Ron & I felt that a fill pressure of 2300 PSI would give the rifle enough shots for sighting in plus the 25 shots needed per card. Velocity spread for the 36 shots was a low of 789 and a high of 808 fps for a spread of 18 fps. I felt that was pretty darned good for an unregulated gun.

Next was pellet testing. I cleaned the barrel and sighted it in with Air Arms pellets. The score was not that great, 223. Again, the barrel was cleaned and the rifle filled and sighted in with JSB pellets. The score improved to 235. Cleaning, filling and sighting in with the AA pellets yielded a score of 228 on target 3. I credit the improved score over target 1 to paying more attention to form and consistency. Again, cleaning, filling and sighting in with JSB's, the fourth target score was 233.

Conclusions: JSB Diabolo Heavy pellets seem to be superior to the Air Arms pellets at this velocity setting. Form and consistency count. The rifle has the potential to shoot in the 700's. No, this rifle with not ever be a 750 rifle. I knew that from the get go. But, if it shoots 700 plus that puts the gun in the 93 percentile. And, would anyone really consider that to be bad for a $510 MSRP rifle that can be bought for $399?

The bottom line is that I am having fun seeing what the potential for this out of the box, not customized rifle with a $65 scope is capable of.

Steve W.
 
Having fun out of the box is great. I lent my Hammerli Pnuema to a friend and he broke the barrier outdoors with a 704. Larry Engle is a mater class silhouette shooter and enjoys kidding folks that sit down to shoot.
 
I'm not sure if you tried this, but with my Marauder, I throttled the transfer port to the max, causing a much lowered velocity, then I reset the striker stroke to full to get the charge pressure up closer to 3,000, ending with around 785fps with 8.4gr JSB's. I get around fifty consistent shots, and could shoot the gun in LV class if I wanted.
 
Thanks Bob & LD!

Ron was kind enough to share an Excel spreadsheet he had developed for analyzing air rifle power curves. I built the sheet last night & emailed it to Ron for his review. He rearranged the data a bit and revised the graduations on the chart to provide a better visual representation of the power curve. If you are interested in seeing the results of our work yesterday, click here.
 
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If you recall, my goal (other than promoting this fine shooting sport & the new Production class) was to shoot into the 700's. Long story short - YAHOO! Today was the day! ;):eek::) 240/4X, 246/9X, 240/4X total 726/17X I am still on a euphoric high! Went right through 700 into the 720's!

Now, you may ask, "What changed, what did ol' Steve learn/do differently?" First, Ron & I tuned the Marauder and tested it thoroughly with different pellets. I do believe that reducing the velocity below 800 fps made a major difference. Then we found the magic pellet for this particular Marauder, JSB Diabolo Exact Heavies.

The third and fourth changes were placement on the bags (thanks Steve G.) and letting the rifle free recoil. In essence, I am now shooting it like a FWB P70FT (with somewhat lower scores of course) :).

Ron was sighting in his new RAW TM1000 today. I was talking with him between target 1 & 2, and he explained that he leveled the rifle in the rest then leveled the target. He then made sure that vertical cross hair was vertical as well. That got me to thinking that I was not paying attention to any slight cant of the rifle shot to shot. I had always hung my target level; thus, I started checking the vertical shot to shot. That made a slight difference as well.

Now, the goal is to see if the Marauder and I can stay in the 240/720+ club! :) More on that as it unfolds!

Steve W.
 
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Wow, Steve!

729 is really, really good for a stock gun, ESP considering you were only targeting for 700 not so long ago! I think mine and shoot into the 700's, but not so good as 729 around here, uless I get one of those one in a hundred days with almost no wind (we had one around a year ago or so here).n But hay, don't quit, if yo can jump from below 700 to near 730, why NOT 740?

BTW, this is still with no mechanical rest, no?
 
Hi LD,

You are correct, no mechanical rest. I have 2 Protektor bags. If memory serves me, they are a 7A & 13. & I will continue to attempt to increase scores. My next hurdle will be to try to break 730. Then we will head to the 740 bracket! :)

Steve W.
 
Great Scores Steve! Indoors or outdoors ? We are shooting in a tree lined narrow lane where the wind changes at every tree. Excuses Excuses he he. I see you topped out best score with a Hammerli by Larry Engle. A couple of us will try the USBR target Sunday. I will give it a try with my Theoben 30 ft lb.

Keep up the good ShootN'

Bob
 
19Turkeys said:
If you recall, my goal (other than promoting this fine shooting sport & the new Production class) was to shoot into the 740's. Long story short - YAHOO! Today was the day! ;):eek::) 240/4X, 246/9X, 240/4X total 726/17X I am still on a euphoric high!
Click to expand...

Great shooting Steve, you should be euphoric! That is an incredible showing of shooting skill and rifle tuning, you and Ron make a pretty good team. Keep going, 740 is within your reach.

Jim in Sacramento
 
Well, it wasn't a 720+ today, but I still broke my original goal of shooting into the 700's! :) The first (& worst) score was 231/1X followed by a 239/5X & a 239/2X for a total of 709/8X. I will be happy if I can consistently shoot into the 700's with an occasional burst of brilliance allowing me to shoot into the 720's or maybe even a 730+ score!

As I tell my fellow IHMSA silhouette shooters, it is not the targets you hit that bring you back, it is the ones you miss! Thus, a sub 720 score today will bring me back next Wednesday to finish up my 15 targets. Until then, shoot well and thanks for following this humble thread.

Steve W.
 
Steve,

I have recruited a new shooter at our club and he is testing pellets and hammer spring, and striker settings on his Marauder. We have gradually reduced velocity and we are working now with JSB heavy pellets. One key factor in your experiments that I may have missed and consider important with my Hammerli, That is the fill pressure. A variation here will increase velocity or lower velocity assuming no changes in the other settings. We had a chony string today that was mid 30's extreme spread. I think that the famous un-regulated USFt gets great accuracy with a 40 spread. With a much larger tube I think the fill pressure is much less than what we are using. Both Jimmy and I are charging at 2600 psi.

When you went to the JSB Heavy from the lighter AA pellet which is also a JSB, did you change anything or just shoot at the lower velocity? My chairgun program show a JSB 10.3 at 849.2 is 16.5 ft lbs.

What is your fill pressure?

One thing that we have done as to front rest. Most everyone that has shown up has a rest of some kind, some better than others. We allow any front rest with no adjustments if the rest has adjustment It made no sense to us to have someone make an additional purchase of another bag and a base to get some height.

The key is we are adding shooters.

What is your first shot velocity and your last accurate shot? What is the average with JSB Heavy. How many shots?

Bob
 
Hi Bob,

Here's a PDF document that will answer your questions concerning velocity, shot string etc. Click Here.

We have taken fill pressure into account. I fill to 2400 PSI on the Marauder gauge which I have found reads about 200 PSI light. My current DIN to Foster fill adapter is really a Cheap Charlie rig. I have ordered a new microbore 3 foot line with gauge from Joe Brancato and should have it next week. I will fill to 2400 on the Crosman then know what the actual pressure is.

If I have not answered your questions or your shooter would like to communicate directly, my email is steve at sworegon.com. And congratulations on getting a new shooter! Production class works!

Steve W.
 
I have finished my fifteen targets; thus, my indoor season is over. I experimented a bit with placement of the front bag, and I believe more study of that is required. I am pleased to report that my three scores were 240/4X, 242/4X & 238/9X. The 238 was shot with a different front bag placement. While I was 2 points off a 240, the X count was more than double. Thus, my belief that more study in this area is needed.

The next chapter of this saga will discuss how pesky SW Oregon winds cause a sense of insecurity on this old shooter! Humble opinion, I will be pleased if I can keep the scores in the low 700's! :)

And thanks to all that have been following this adventure.

Steve W.
 
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