Author Topic: 7mm 08 sighting in problem (Read 2719 times)

texashooter · « **on:** January 28, 2008, 08:49:03 AM »

I just got the Optima in 7 mm 08 , took it to the range twice and I have had real issues getting it grouped.
I have a 3x9x40 Pentax scope, I first loaded up Serra Game hunter 120 gr bullets on top of IMr 4064 to the suggested starting load in my Lyman book. Didn't work out to well. So I read that Hogdon 380 was the best powder to use on the 7mm 08 so I got some of that loaded the same bullets on top of the suggested starting load on the Hogdon web site and still no good groups. Shots seem to wander where they want part of the time. Three rounds bottom right in about a 3.5 in group. Adjust the scope, one dead on , one bottom right , one in the middle of the other two. This went on for several rounds.

Any suggestions ? I thought that my next step might be to just go buy a box of factory rounds to see if they would do better then switch over to my reloads after that (if I could get them to group a little better)

quickdtoo · « **Reply #1 on:** January 28, 2008, 09:24:28 AM »

If the point of impact is changing, I'd check the scope and mounts before trying to work up a load, and just picking a start load isn't going to guarantee an accurate load unless you get real lucky, I work up in ½gr increments, 3-shots each, from start data and always find a suitable load somewhere before I reach the max, then fine tune that load by adjusting seating depth if I want to improve it. If you OE has the muzzleloader forend, it may not be as accurate as the centerfire forend, at least mine wasn't.

You can also try shooting it rested under the frame instead of the forend, with the forend off, if it shoots to the same POI and the groups are tighter, the forend needs work. As a last resort, give Mark a call or email and ask for help, see the CS sticky.

Mine shoots the 160gr Accubond with Rl19 very good.

Tim

texashooter · « **Reply #2 on:** January 28, 2008, 10:51:16 AM »

Thanks, I double checked the scope mounts they were tight , I would be happy if the thing would just stay in the same 5-6 inch group for 10 shots. Then I would start changing the loads .5 gr at the time as you suggest. That was my plan going in. Right now I am a little frustrated with it. I think that I will try a box of factory loads just to see what they do in it. Then I will see where to go from there. I may have too many variables involved using the hand loads, new gun, new scope all at one time.

quickdtoo · « **Reply #3 on:** January 28, 2008, 11:25:46 AM »

Did you loctite the base(s) in place? Are you using a one piece or two piece base? That would be where I'd start. Mounting a known good scope would be the next step to eliminate the scope as a problem. I started to use a two piece Warne set on my 300 WinMag barrel, but they were so close together that it didn't allow any fore and aft positioning of the scope and the scope rings supported the scope too close to the center of the tube for my liking, so I went with another Durasight base, see the sticky on that issue too for more info.

My 7mm-08 didn't like the Rem and Fusion 140gr as much as the handloads, but it still grouped in 1½"-2".

Tim

texashooter · « **Reply #4 on:** January 29, 2008, 03:49:13 AM »

Thanks for the input, I have the one piece Durasight base that CVA recommends for the rifle. When I checked the scope mount it was not lose , so I didn't pull it off and remount the base. I thought about putting another scope on the gun. Think that may be step after next. I think I need to work one issue at a time or try one thing at a time to see where the issue may be. Keep it as simple as I can , I really need simple when it comes to getting these things set up sometime. Thanks for all of the good input. I really am starting to think as well that the bullets just might be a little light for the rifle. One thing that I have found is that most of the people who hunt with them are using the 139 gr bullets. I might end up trying them with starting loads to see how they do. One question , the bullets that you are using on your hand loads are they flat based or boat tails ? The ones that I am trying right now are flat based. I know most people will say that should not make a difference, but I have seen it affect different guns in the past.

quickdtoo · « **Reply #5 on:** January 29, 2008, 06:30:56 AM »

I picked the 160gr Accubond due to the 1:9" twist, figured it would be a good barrel to shoot them in, Nosler had them for a very good price in their seconds, it's a boat tailed bullet.

Tim

Tunaman · « **Reply #6 on:** January 29, 2008, 07:34:03 AM »

I too would check the scope. I have exactly one Pentax (Game seeker) and have had no luck with it. My OE on the other hand has been great and shot well. I seriously suspect the scope.

texashooter · « **Reply #7 on:** January 29, 2008, 08:43:42 AM »

Yea I do as well suspect the Scope, I read really good things about it before I bought it, I even compared it in store to the Nikon and I could see much better through the Pentax than the Nikon ! It seems either people love them or hate them no in between.

Well I will keep trying things out. One thing I noticed is the length of the bullet that Tim is using is much longer than the 120 Serra bullet that I am using. Here is the link to the one that I have been using

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=606399&t=11082005

quickdtoo · « **Reply #8 on:** January 29, 2008, 08:55:10 AM »

They aren't to the same scale obviously, but there is a big difference in their length.

texashooter · « **Reply #9 on:** January 29, 2008, 11:21:02 AM »

Well the bottom line issue could be the length of the bullet itself. Could be that due to the twist the shorter one is just not as good for that length of barrel and twist , humm..
Still think I will try of off the shelf stuff then go with a bigger/longer bullet IF the off the shelf stuff works any better.
This is all good information a lot of things to think about. I am sure that at some point I will make a nail driver out of this gun, heck I love the heck out of shooting it ! so I have to get it right.

quickdtoo · « **Reply #10 on:** January 29, 2008, 11:24:58 AM »

For reference, I can touch the lands with the 160gr AB loaded to a COL of 2.892", my loads were .003" off the lands at 2.889".

Good luck and have fun!

Tim

texashooter · « **Reply #11 on:** January 30, 2008, 05:34:54 AM »

Thanks I am going to try to get out again this weekend and try it out again. I will update you on the results.
Thanks again for all of your help

texashooter · « **Reply #12 on:** September 07, 2008, 12:29:16 PM »

Finally got back to the range , its been 6 months now , the gun is grouping much better , dont know for sure what I did but its working better. The factory loads grouped really well. I have purchased a box of Hornady 139 gr sst's to load up for hunting season, I have several different documents with load data but the one that I dont have is the hornady manual. Does anyone on here have the latest hornady manual ? would like to know the load data that Hornady that they suggest since they make the bullet. If anyone has it could you send me the load data for the 7mm 08 hornady 139 gr SST , using H380 powder.

Thanks

bubba · « **Reply #13 on:** September 10, 2008, 02:38:54 PM »

I know it is not what you asked and no two guns are the same but, My oe 7-08 shoots 140 grain remngton corelokt over 41 grains of varget. I have the one piece base and a bushnell banner 3x9x40 on it. at 100 yards it shoots 2 1/2 inch groups which makes me very happy for a deer rifle. I am very impressed with varget for sure

texashooter · « **Reply #14 on:** September 11, 2008, 09:43:45 AM »

I loaded up 20 of the Hornady 139 SSTs last night using the recomended charge from the Hogdon web site of 44 grs. I will have to wait a couple of weeks to try them out since IKE is headed this way for this week end and I will be out of town next weekend. Need to get this done , deer season starts Nov 1 !

texashooter · « **Reply #15 on:** October 08, 2008, 03:53:48 AM »

Ok I give up on the gun, this morning I sent Mark a email , he called me with in 30 mins ! He told me to send it in and they will take care of it. This is what customer service is supposed to be like. Heck of a nice guy and really a lot of help and relief.

Just a side note , before giving up , I changed out scopes shot 4 different kinds of bullets/loads etc, used a lead sled, had someone else try it. The only thing I think that it can be is the barrel. We will find out.

bubba · « **Reply #16 on:** December 03, 2008, 01:10:49 PM »

any updates from CVA and the rifle?

OptimaAndy · « **Reply #17 on:** February 03, 2010, 10:32:59 AM »

what was the outcome?

quickdtoo · « **Reply #18 on:** February 03, 2010, 11:08:19 AM »

The OP hasn't been back here since Dec 2008.

Tim

OptimaAndy · « **Reply #19 on:** February 03, 2010, 01:56:29 PM »

looks like you have been here since Jesus wore sandals, Do you remember what the outcome was. Today i tried sighting in my 243 and started out good at 25. moved out to 509 and things went to heck. I would have a good 2 shot group right of center and then a flyer to the right. Walk down to mark the shots come back fire 3 more and it would do the same thing. went thhrough 2 boxes of remington express core lokt 100 grain and couldn't get a good enough group to adjust anything. I kow its not me flinching or anything. Its either the ammo or the scope. Gonna try some federals this weekend.

quickdtoo · « **Reply #20 on:** February 03, 2010, 02:39:29 PM »

Start by checking the scope base(s), be sure the screws are tight and loctited in place, then move on to the rings and scope.

Tim

OptimaAndy · « **Reply #21 on:** February 03, 2010, 03:05:54 PM »

everything seems tight. Didn't crank it to hard but it seems solid. I thinks its just the ammo. Will know more after shooting some federal fusions.
thanks

OptimaAndy · « **Reply #22 on:** February 09, 2010, 10:13:12 AM »

yup, it was the ammo