Prohunter encore - making it more accurate

[Traps]

After numerous times to the range and looking for that magic combination of powder, bullet, seating distances off the lands, I have come to the conclusion that a newly purchased prohunter is on average a 2-3 MOA gun from my gun experience and all the review I read on it. Am I surprised, not entirely but thought that it would do a a little better than 2-3 MOA. Anyways it has gotten better over the progressive upgrades and today I found the winning combination. I'll start from the beginning:

Stage 1: new encore - no upgrades - shot factory ammo
Best groups - 6 MOA

Stage2: My rings/scope not properly secured, deburred, loctighted, and tightened
Best groups - 3 MOA

Stage 3: New oversize pin installed from Mike Belm, stronger lockup spring, replaced trigger spring from a 5lb to 2.5 lb trigger.
Best groups - 2.5 MOA

Stage 4: No upgrades just figuring out what powder works, 200 grain etips and Win 748 give at best 2 MOA, 185 barnes tsx over Re15 gave 2 MOA at best, nosler accubonds decent at 2.5 MOA with H4895, 210 TTSX and H4895 2 MOA

Stage 5: Chrono handloads and factory ammo. Beating factory ammo listing - Barnes 185 TSX listed at 2750 fps, I am getting 2820 fps - happy as punch.
Handloads - I am getting 2600 fps with 200 etips and Win 748 - starting to get warm but pressure is the lowest of the bunch at this velocity and accuracy is 2 MOA. This is my hunting load for last year.

Stage 6: Shave material from the sides of the forearm where it meets the receiver and place two cleaning patches one on either side to "free float" when I torqued the forearm in place. Removed patches after secured.

Took some material out of the one inner rib that was rubbing on barrel.

Tightened the stock socket head below the pistol grip TC emblem cap, I could still move the barrel back and forth. Took another cleaning patch and place it between the barrel and the receiver just rearward of the hinge pin. No slop now between barrel and receiver - not a permament fix but shot it like that. These things are the ticket in the prohunter, or at least mine.

Best groups - With Re15 and 185 TSX getting 1/4" to 1 3/8" groups if I do my part. Some two groups are now same hole, never had that before in this rifle. Barnes like a jump to the lands, Etips like it closer to the lands. Happy as punch, now gonna play around with Re15 and TSX some more and go back to some of the other loads that gave decent results.

I've had a dozen or more of them and they've all shot sub 1.5 MOA out of the box and usually better with a bit of bullet tinkering. The occasional one definitely benefits from an oversized hinge pin and I've had the occasional vertical stringing problem when the rifle got hot due to forestock pressure but overall, mine have been great shooters.

I'm confused about your comments about tightening the hex screw in the piston grip. All it does is hold the rear stock to the receiver. It should have no bearing on how tight your barrel fits to the receiver.

[Traps]

I also experienced vertical stringing on heating.



I'm confused about your comments about tightening the hex screw in the piston grip. All it does is hold the rear stock to the receiver. It should have no bearing on how tight your barrel fits to the receiver.

In the past the socket bolt would come loose and the rifle would pivot awkwardly and my groups would go to hell. This last time I grabbed the forestock with one hand and held the butt of the gun with the other and put some side force left to right on the forestock and there was play. Initially I thought this was solely due to the socket bolt being loose but after tightening it more there was still side to side play. I repeated the side to side force and noticed the gap between the barrel and the inside of the receiver changing. Thats when I took a cleaning patch and placed it between the inside of the receiver and the side of the barrel as I locked it up. Now on lockup its tight.

[powerman]

When I got my pro-hunter I had to sand down the forgrip a bit because it was rubbing on the barrel. I was not sure what I thought of the rifle at the range, but got it making reasonable groups. I decided that I would try hunting with it before I decided to keep it or sell it. After hunting with it I have resolved to fix the rifle. I have purchased reloading equipment to try to perfect a load for it. I have to look at some of the problem areas that you had. Thanks for the info on your fixs Traps. One thing I have been wondering about is putting some appoxy in the forgrip to try and make it a little more solid. I find it has some flex to it that may cause some of the problem. Any thoughts?

[Traps]

Originally Posted by powerman

When I got my pro-hunter I had to sand down the forgrip a bit because it was rubbing on the barrel. I was not sure what I thought of the rifle at the range, but got it making reasonable groups. I decided that I would try hunting with it before I decided to keep it or sell it. After hunting with it I have resolved to fix the rifle. I have purchased reloading equipment to try to perfect a load for it. I have to look at some of the problem areas that you had. Thanks for the info on your fixs Traps. One thing I have been wondering about is putting some appoxy in the forgrip to try and make it a little more solid. I find it has some flex to it that may cause some of the problem. Any thoughts?

If your foregrip is loose tighten it to 30 in-lbs and check it for how solid it is. If its still loose take the foregrip off. You'll see ribs inside the foregrip and two bosses that the two bolts pass through. On mine I noticed the contact points (seen from the rub points on the barrel) were on the very rear, the rear rib, and the front boss. All the other ribs near the front boss/bolt weren't touching. I sanded the rear rib smooth so it contacted evenly on the barrel.

I figure accuracy is maintained from shot to shot by elminating variables, every time the foregrip is taken off and put back on it changes the setup, that includes being loose or wobbly. An evenly supported eppoxyed barrel should be better.

Traps, this is a very interesting chronology of your ProHunter experience but I'd guess that if you'd just mounted the scope properly in the first place and then experimented with a few loads that you'd be shooting the same sub MOA groups that you are now. I really doubt all the other things you did made any difference. These guns are for the most part great shooters out of the box. I take forestocks and barrels on and off al the time without effecting accuracy at all. That's the beauty of the gun.

Quite honestly, the forestock doesn't make any difference unless its creating a pressure point. The gun will shoot identically with or without it in place. It doesn't support the barrel, it hangs off of it. It's really nothing more than a place to put your hand while shooting.

[Traps]

Sheep, by the sounds of it I don't think I'll convince you, but its good to hear you didn't have any problems.

[powerman]

I shoot off of a bi-pod and have found that the forstock flexes. This is why I am thinking of putting some eppoxy in the forstock. What are your thought on the flexability if the forstock? Also I found that there is some play in the stock so I might try taking the stock off and put a cleaning patch around it and tighten it down.

I'd be more worried about creating a pressure point than fixing one by adding epoxy. The best thing that can happen is that a forstock not touch the barrel. What you are calling flex is actually the barrel floating above the front of the forestock. That's desireable. The forestock on a ProHunter serves little purpose other than being a hand hold. If there are no pressure points on it, why create some?

[oagie]

I have done quite a bit of reading on the prohunter because eventually I want to get one. One of the site I did come across (I think it was a custom gunsmith site, I forget which one). He did say that even with these guns you can still get a bad barrel.

Thousands of barrels are turned out of the factory and pass their QA tests. Obviously their quality assurance might not be the same standards as an experienced shooter as yourself. So, there is a possibly you might have a sub par barrel.

So, if you are able to, experiment with another barrel. Even if its a borrowed one of a different caliber. Your expense would be a box of shells.

BTW, what caliber are you shooting?

[Traps]

Originally Posted by powerman

I shoot off of a bi-pod and have found that the forstock flexes. This is why I am thinking of putting some eppoxy in the forstock. What are your thought on the flexability if the forstock? Also I found that there is some play in the stock so I might try taking the stock off and put a cleaning patch around it and tighten it down.

The forestock is somewhat flexible but for the most part if its bolted down with no pressure points if should be secure. I like your idea of using the cleaning patch to take out the pressure points, cheap and easy short term fix, and it takes very little to check out differences in accuracy.

[Traps]

Originally Posted by oagie

I have done quite a bit of reading on the prohunter because eventually I want to get one. One of the site I did come across (I think it was a custom gunsmith site, I forget which one). He did say that even with these guns you can still get a bad barrel.

Thousands of barrels are turned out of the factory and pass their QA tests. Obviously their quality assurance might not be the same standards as an experienced shooter as yourself. So, there is a possibly you might have a sub par barrel.

So, if you are able to, experiment with another barrel. Even if its a borrowed one of a different caliber. Your expense would be a box of shells.

BTW, what caliber are you shooting?

Its quite possible I got a bad barrel receiver combo. I have two barrels one a 7mm-08 and the other a 338 Federal. All the info above was for the 338 Federal. The 7mm-08 shot a little better but nothing to write home about.

I found this on a TC barrel from the guy I bought my oversize pin from, their QC may not be all its cracked up to be.

http://bellmtcs.com/store/index.php?cid=168

I also came across this writeup on the same website, its errie how similar it is to what we are discussing about the forestock. The part about epoxy is addressed in this with promising results:

http://bellmtcs.com/store/index.php?cid=439

Enjoy the read fellas.

Am I missing something Traps. All I read was him pillar bedding the forestock to remove the pressure points.

[Traps]

"I machined a couple of steel pillars and installed them in the forend giving it a good .025 off barrel except for the pillar contact. Also removed a lot of material off the sides where it had been touching the barrel. After the epoxy got good and cured, off to shoot it again."

Sheep he epoxied the pillar contacts and added steel pillars. Were you looking for more?

Originally Posted by Traps

"I machined a couple of steel pillars and installed them in the forend giving it a good .025 off barrel except for the pillar contact. Also removed a lot of material off the sides where it had been touching the barrel. After the epoxy got good and cured, off to shoot it again."

Sheep he epoxied the pillar contacts. Were you looking for more?

I think he just epoxied the pillars in place....that's a long way from adding epoxy to the foresock to stop flex or increase barrel contact. What he did actually decreased barrel contact and I'm sure involved a minute amount of epoxy. I didn't see anything about the part with epoxy offering promising results. The pillars helped no doubt as I'm sure they would but the epoxy simply held the pillars in place. The epoxy would have done nothing without the pillars.

[Traps]

He did only epoxy the pillars. Epoxy on the pillars is critical to make sure the pillars are contacting the barrel evenly on the contact points, in this case the ribs and the pillars.

I think your misunderstanding the discussion in that we would do the whole forestock which wouldn't be good. Remember powerman said "One thing I have been wondering about is putting some appoxy in the forgrip to try and make it a little more solid." key word here is "some" which I said to eliminate variables go to an evenly contacted barrel, not fully contacted, otherwise it would be a one barrel rifle.

I think you are reading a bit too much into what he did.

[Traps]

I found out from a member on Cdn Gun Nutz what they call a hanger system to mount between the barrel and forearm and a tensionable pin. He seemed to have good luck installing the tensionable pin, and that made his groups better by taking out the side to side play. It makes more sense than an oversize one in that as it wears you can tighten it up or if one barrel has a hole slightly different than another. Cabelas sells them I believe. The tensionable pin will be the next purchase.

Traps, you're getting .25" groups out of this rifle and you're worried about accuracy?

[powerman]

I am talking about putting some eppoxy in the forstock. Not enough to touch the barrel, but enough to add some stability to the forstock. I think there may be enough play in the forstock to cause a jump when I shoot. I like the idea of a tensionable pin. I will have to look at it more.

[Traps]

I just took a look at the tensionable pin (they call it the locker pin). It takes care of side to side movement only so it won't take care of diametral clearance. The Belm pin takes care of diametral clearance. Would be nice if it took care of both.

Cabelas pin:
http://www.cabelas.com/p-00491612164...roduct-reviews

Belm pin:
http://bellmtcs.com/store/index.php?cid=445

[209x50]

Originally Posted by powerman

I am talking about putting some eppoxy in the forstock. Not enough to touch the barrel, but enough to add some stability to the forstock. I think there may be enough play in the forstock to cause a jump when I shoot. I like the idea of a tensionable pin. I will have to look at it more.

Cause a jump? I don't follow you on this.

[powerman]

It may not be much of a jump, it is something i am looking into. I have to shoot it some more and I know have a leadsled to shoot off of, so I will see if there is a jump or if it is me.

Powerman, are you talking about muzzle jump caused by recoil?

[powerman]

No, and yes. Take your prohunter and sqweeze the barrel and forstock together at the sling lug. See how much flex there is. Do you see that as a problem when shooting of a bi-pod. Even the weight of the rifle will cause the forstock to flex when set down on the bi-pod. I think this creates some potenital energy, and releases like a spring when shot, causing exessive jump and vibrations. Just a theory. Controling the variables is important, and this is a big variable even when shooting off hand. I am thinking of putting eppoxy in the forstock, filling to just below the top of the ribs. This will tighten up the forstock and still keep the barrel free floating and be able to swap barrels out. Am I over thinking this or does it sound like a fix to a problem?

Originally Posted by powerman

No, and yes. Take your prohunter and sqweeze the barrel and forstock together at the sling lug. See how much flex there is. Do you see that as a problem when shooting of a bi-pod. Even the weight of the rifle will cause the forstock to flex when set down on the bi-pod. I think this creates some potenital energy, and releases like a spring when shot, causing exessive jump and vibrations. Just a theory. Controling the variables is important, and this is a big variable even when shooting off hand. I am thinking of putting eppoxy in the forstock, filling to just below the top of the ribs. This will tighten up the forstock and still keep the barrel free floating and be able to swap barrels out. Am I over thinking this or does it sound like a fix to a problem?

Take any quality rifle of any brand and you'll see that same movementment. You definitely don't want to fill that gap. All you'll do is greate a pressure point and turn an accurate rifle into an inaccurate one. From where I'm sitting you don't have a problem but you are about to create one. The only way to "tighten" up the forestock is by creating barrel contact and you definitely don't want that.

[Huntnut]

Originally Posted by sheephunter

Traps, you're getting .25" groups out of this rifle and you're worried about accuracy?

X2

And here I thought I was doing good buy getting just under an inch groups with mine.

[209x50]

Originally Posted by powerman

No, and yes. Take your prohunter and sqweeze the barrel and forstock together at the sling lug. See how much flex there is. Do you see that as a problem when shooting of a bi-pod. Even the weight of the rifle will cause the forstock to flex when set down on the bi-pod. I think this creates some potenital energy, and releases like a spring when shot, causing exessive jump and vibrations. Just a theory. Controling the variables is important, and this is a big variable even when shooting off hand. I am thinking of putting eppoxy in the forstock, filling to just below the top of the ribs. This will tighten up the forstock and still keep the barrel free floating and be able to swap barrels out. Am I over thinking this or does it sound like a fix to a problem?

No matter how much that stock flexes as long as it doesn't touch the barrell or put pressure on it there is no effect on the shot.

[powerman]

glad I could bounce the idea off of you guys. I was not sure what would happen, that is why I have not done it yet. Thank you.

[Traps]

After all the different things that I tried I would say that the two biggest contributors to improving my groups from the list of things done are the oversize pin and putting the cleaning patch between the barrel and receiver. I found that with a lot of use (about 500 rounds) the oversize pin has become loose over use. Anyone have any ideas for a permanent fix?