Dear all

Just wondered what your thoughts were on my most recent trip to the range. Basically I have a .25-06 Accumark which I was hoping to develop a load for.

To cut a long story short I could not get the rifle to consistently perform. A load that I thought I had cracked it with was 55 grns of AA3100 behind a 100 grn Sierra Pro Hunter. Fed brass and fed 210M primer.

Bullet was seated 40 thou off the lands. First 3 shot group with this load was approximately .25 inch. I loaded 3 more rounds up to check consistency (expecting them to perhaps go .5 or so) and they opened up to 1.3 inches!! Same everyting - I didn't change a thing.

This is the 4th .25-06 I have had over the years and this is consistent with what I have found with the previous 3 I have had. That is to say that they have all been very inconsistent.

Is it just me or is this cartridge particularly fickle?

I would love to hear from other .25-06 owners out there to find out if my experiences are common to all.

Many thanks

Both my Rem 700 BDL and my Colt\Sauer sporting rifles would heat up the barrel real fast causing stringing of the group. But once in the game fields, I never had the occasion to shoot that many rounds at any fleeing animal. The first shot from a cold barrel was always on the money. And since the game laws prohibit mowing down the herd, the first shot is all that counts.

I've been loading for the 25-06 Rem for 38 years. I've not found it finicky. Except to learn that both my rifles did not like 117 or 120gr Sierra bullets. Berger 115 VLD's perform better for some reason.

Learning what your rifle likes is all part of the handloading experience.

I would have to suspect that the problem is the rifle, not the load. Your load looks like a good one to me and those Sierra Pro Hunters will shoot.

I have several friends who had accuracy problems with Weatherby Mark V's. For all their claims of a warranty, Weatherby was of no help at all. They pretty much simply did not want to hear about it. These rifles gave very poor accuracy and just the type of inconsistancy you are talking about.

My friends did everything from selling the rifles to sending them off to Hill Country Accurizing in Texas for work. (Hill Country does a hell of a job on a rifle, just kind of expensive.)

You may find a load yet that will work for you, but I bet it is the rifle that is at fault. My custom made 25-06 is very consistant and will amazingly put just darned near any weight or brand into the same group.

I've been shooting one since 1974 and will be building another in the future. It's one of my favorites and will be my Godson's first big rifle from me.
My "go to" load has been 52.3g H4831 w/ Nosler 120 Partitions. I've also loaded everything from 75g hornadys up. My rifle shoots everything 3/4 or less w/o complaining UNTIL it tells me it needs cleaning and then the groups open. Once cleaned, the groups majicly shrink. In my younger days I shot this rifle much more, but it does seem to "foul" rather quickly. Maybe the factory barrel is rough. I've JB polished the bore and I'm sure will find out if it helped when the Godson starts wanting to bleed everything w/ hair on it!

quote:

Originally posted by Jon2:
Dear all
-----
First 3 shot group with this load was approximately .25 inch. I loaded 3 more rounds up to check consistency (expecting them to perhaps go .5 or so) and they opened up to 1.3 inches!! Same everyting - I didn't change a thing.

-------

Is it just me or is this cartridge particularly fickle?

I would love to hear from other .25-06 owners out there to find out if my experiences are common to all.

Many thanks

Mine have not been inaccurate or fickle at all.

Barrel heating as mentioned above sounds possible, --over what length of time were the shots fired?

Bedding is another possibility, as are scope mounting/ reticle movement.

Fouling with 3100 is another consideration.

And/Or--all the above.

As to the Weatherby's being accurate --have shot many, the Accumarks in general live up to there name-sake.

I've been shooting 25/06 for 20+ years. I've tried most of the powders that you find in the loading manuals. I have always found that my rifles prefer 100gr boat tail bullets and IMR4831. I am now preparing to try RL22 just for kicks!
I have never found any of my quarterbores to be finicky about what you shoot in the and it has always been easy to find what they prefer.
GOOD LUCK and GOOD SHOOTING!!!

sounds alittle like you might have something pushing the barrel around a bit(bedding?).....
with that said, i have to also add that i have all but given up on the 25-06 a long time ago. i've had a couple, rem 700 and a "custom", on a interarms MK-X built by a good smith and i never got either one to shoot consistantly well either. it's just another one of those overbore cartridges that create nothing but headaches and won't shoot the same from day to day. your problem might not be the load, just as Rflowers suggests, but it's been my experience (and my gunsmith's) that the round is indeed fickle and an problem child. it will shoot if you find the right combination, but finding that combination is like finding a needle in a haystack. i know i've gone through many pounds of /powder/bullet/primers with both of mine and not ever found a load that i could honestly say i trusted to do it's thing all the time,... just about the time you think you've found something that works, it craps out the next time you load a few to confirm it. typically overbore.... maybe it's just me, but i have a hard time believing someone who says they have no problems with the round....i personally have never met someone who doesn't mention or agree that it's hard to find a good load for when loading for the 25-06 comes up.
it seems that there are both sides of the argument posted here, so like most things, i guess you have to make up your own mind!!

My Rem 700 25-06 shot factory 100 gr coreloks around an inch. Started reloading and found the 52 gr IMR4350 and 100 gr nosler BT shoots nickel sized groups at 100 yrds when I can hold her steady. Same load works great in a 700 sendero. 3 of my hunt'n buddies have 1/4-06s and none of them have had troubles finding a 1" load.

The accumark is a fine rifle, I have one in 340 and it prints just fine. First thing to look a is that the action is properly torqued to the stock. Then check all of your scope mounts and bases to ensure they are properly torqued. The check your reloads carefuly to make sure your powder measure isn't drifting a bit.

John

quote:

Originally posted by Jon2:
Is it just me or is this cartridge particularly fickle?

Jon,

Well...being this is the 4th one inconsistence - I'd say you haven't ruled out your reloading technique and your shooting.

• Have you have been able to hold other caliber rifles to consistent 3/8" groups?
  
• Like BBB Hunter - I would suspect that powder measure drifting or
  
• Could it be powder measure set-up? - Such that the inconsistency is batch to batch?
  
• Have you run these reloads across a chrony?

Thanks Fellas for all the replies.

Just to elaborate on the circumstances - I had a perfectly clean barrel. I shot 2 foulers and let it cool completely (15 mins). I then shot a 3 shot group which was perhaps 1" to 1.25" using same charge weight and powder but 100 grn Game King. Then I put the .25" group in with the load mentioned above and then the group which opened up to 1.3". The rifle was left for 15 - 20 mins between groups and also I can't imagine that the level of carbon copper fowling build up of 8 rounds could cause the group to open up 5 fold?? I do understand that fouling is an important factor here potentially but if this rifle is so prone to this after only 8 rounds it will be disappointing. I personally don't think this is the issue.

Ray you make a very vaild point but my brother and I are meticulous in our relaoding techniques. My brother is a perfectionist the the powder measure is a Harrell. We were actually loading for his Howa in .270 using the same measure and he put 2 groups in (first load we tried) one was sub half and the other was about just on .5

We have loaded over the years for various rifles from .22-250 to short mags to win mags etc etc and have never had this "inconsistency" issue which seems to be indicative of the quarter bore. I am not saying that we have every rifle doing quarter inch groups but the .25-06's I have had have proved consistently inconsistent. I even had a Callum Ferguson semi custom (Callum Ferguson has an excellent reputation in the UK) and we were looking at the data from 8 years ago (we keep records of all loads etc) and interestingly this rifle was hovering around the 1.5 - 2" mark with most things we tried. This was a Sako AV action bedded in a Mcmillan with a Shilen match barrel.

Again thankyou for the replies and I am not giving up on this in anyway yet. We have a long way to go with it before we get to that stage. I am however just going to check out the bore with a bore scope next time I am at my rifle smiths. I am also considering bedding and all the other suggestions that have been mentioned regarding accurizing. As I said originally though my concern surrounds the inconsistency that I have seen from this and other .25 cals. It does concern me but I am determined not to let this one escape me. Also all action screws and scope mount screws were/are 100% and I can't see it was heat or fouling either. I am thinking it maybe distance from the lands and out of probably 15 groups of 3 shots it has shown a slight preference to not be on the lands. I also haven't tried a primer change either but again it is the inconsistency that is the issue here.

Thanks all again and I am still appreciative of any further feedback anyone can offer.

Thanks

I've got the WBY 257 V And it shoots just fine.
The 100gr bullets Seem to be the best but the others fly real good Also.

Pick up some Barnes TSX bullets in .257

If it still won't shoot, it's the rifle (or some other unknown factor).

Garrett

I would try a slower powder, such as Norma MRP1, RL22, or IMR 7828. Since the 25/'06 is over bore capacity, it can be more difficult to find the exact load for.

quote:

Originally posted by Jon2:
Dear all

Just wondered what your thoughts were on my most recent trip to the range. Basically I have a .25-06 Accumark which I was hoping to develop a load for.

To cut a long story short I could not get the rifle to consistently perform. A load that I thought I had cracked it with was 55 grns of AA3100 behind a 100 grn Sierra Pro Hunter. Fed brass and fed 210M primer.

Bullet was seated 40 thou off the lands. First 3 shot group with this load was approximately .25 inch. I loaded 3 more rounds up to check consistency (expecting them to perhaps go .5 or so) and they opened up to 1.3 inches!! Same everyting - I didn't change a thing.

This is the 4th .25-06 I have had over the years and this is consistent with what I have found with the previous 3 I have had. That is to say that they have all been very inconsistent.

Is it just me or is this cartridge particularly fickle?

I would love to hear from other .25-06 owners out there to find out if my experiences are common to all.

Many thanks

The one bullet your working with there is the only bullet I have ever had issue with while developing loads for this caliber. I went so far as to call Sierra and get a load from them as everything I tried simply blew. They recommended using CCI primers, and Imr-4350. My normal loads at that time used IMR - 4831 for 100gr loads and with the Nosler Ballistic tip shot many 3/8 - 1/2" groups at 200yds. With the Sierra I was lucky to get anything under 2" at 100. Once I went with their recommendation the groups with the Sierra went into the same little clovers or just one slightly enlarged ragged hole.

Other than Sierra's I have shot Nosler, Hornady, Barnes, and Speer bullets into similar groups. I have used the same data to load for several other both factory and custom rifles in this caliber which all shot very well. I will add this, after working so much initially with my own rifle and various loads, I stuck with a 3.250" OAL for everything and it has worked very well in all of the other rifles. Somehting you might give a try.

Other than that I would add to what another had posted about issues with a rub in the barrel channel, or possibly something shifting in the recoil lug area. I had a .270 which for many years shot the same load time and time again into 1" groups, and all of a sudden the third and succeeding shots would all be flyers. Turned out the area behind the recoil lug was wearing and allowing the slightest bit of play in the action even when the screws were tight. I happen to find it by accident, and once repaired with some bedding compound, the rifle actually shot the same load quite a bit better.

I wish you all the best with your 25. I have enjoyed more than a decade of shooting mine at both targets and game. It has been one of, if not the most accurate rifle I have owned.

Again good luck with yours.

Mike

Thanks. Top info. Very interesting about your .270 with the issue surrounding the recoil lug etc.

I have been thinking of trying IMR 4350. I will take on board your suggestions and definitely try what you suggest.

Thanks

Inconsistant rifles take time. Lots of time and repeated trips to get to the bottom of things. Sometimes you can't cure it.

It took me 3 years to realise that I cannot shoot my long whippy barreled 234 with a bipod. If a hunting rifle can't be trusted to be consistant in the sort of inconsistant enviroment that is hunting then it doesn't get used much.

Inconsistancy can be expensive in time, money and effort. When the search for consistancy ceases to be a fun challenge and becomes frustrating is IMHO when a rifle gets sold.

I have had occasions where a good group appears to have been a fluke and I have had occasions where I have never been able to regain accuracy after changing bullet or powder lots. Warn barrels can be very finicky. Cleaning can be bad news.

Good luck!

I have 5 25-06 rifles and they all shoot -3/4". I've been using the 25-06 since 1976, and both of my children grew up with Rem 700s in 25-06 and took antelope, deer and elk.

That said, my steps have always been:

1. Be sure that the barrel is floated - no contact with the stock forward of the action.

2. Check action screws.

3. Check scope base and mount screws, as well as ring alignment.

4. Clean barrel thoroughly. Bore scope it for imperfections.

5. If I don't have a load that I know to be consistent, then I go to Winchester factory loads - 120 gr. PEP, so that I have a constant to work with.

6. After 3 to 5 shots check the barrel / stock contact again to see if it changed with the hot barrel.

The fact that you can get three good shots and then it changes suggests to me that your barrel is changing after it gets hot.

My Husqvarna rifles really prefer 120 gr. bullets. The Rem 700s are good with 100 gr, 115 gr. and 120 gr. I always use either 4831 or 4350. None of the rifles are picky about brass or primers, although I really prefer Federal Gold Medal Match which I can't get anymore.

Best of luck. I hope you get it worked out because the 25-06 is an outstanding caliber.

Have you used the same reloading dies for all four rifles?

Have you checked bullet concentricity?

i once bought a used Weatherby in 30-06 whose POI would change as it warmed up. First shot was always 4-5 inches high, next one down, third one on the money. When it was warm it would shoot a nice 1 inch group right on the money. Afield it missed an animal one day. I would have to let it cool 30-40 minutes between shots to get it zeroed properly. I finally sold the thing, steel sometimes under stress will relax when its warmer I guess.

Jon2

If you have owned several 25-06's and they have all been fickle the one factor which hasnt changed has probably been your re-loading dies, there could be a problem with them. Try factory loads and see if they shoot more consistently, its not totally off base to think that there could be a problem there. Most, if not all cartridges today can and will shoot very accurately if the conditions are right, if they arent, then thats when problems arise, start with the simplest things first then move on to the more complicated mechanics. If it was the same scope on all your 25-06's then i would also suspect that as well or its mounts...

Thanks Fellas

The dies are not the same ones whch I used on the previous rifles. They were both RCBS though.

Scope is 100%.

I have tried factory ammo and amazingly I got a first group of about .6 and then every group thereafter was about 1.25 to 1.5

The factory was Winchester 120 grn PEP.

Thanks again

Jon2:
I don't have a .25-06 but some things in your comments strike me. For one thing, do you KNOW that your scope is 100%? I've been fighting a Kimber .270 WSM for 3 years. Brand new scope too. I did everything under the sun to that rifle & it still wasn't consistant. It would shoot a good group 1 day then crap out on another. I had changed out the scope sometime back & noticed no difference in performance and therefore assumed I still had rifle problems. Finally, I sent the scope back to the manufacturer and found out that the adjustments were screwed up. I took the rifle out yesterday and it now looks as if it will perform. In short, I think I had both a bum rifle AND scope and I concentrated on the rifle.
I would make certain that your barrel is totally free floated and action screws are torqued to factory specs. I'm sure you've looked at copper fouling as well. One thing I found on my Kimber is that it seems to like a bit of pressure under the barrel. I put some bedding compound under the barrel about 1 1/2" from the end. You might experiment with several business cards slipped into the forearm & see what happens. I can't believe your rifle won't shoot. Good luck. Bear in Fairbanks

I had the same problem with a Mark V rifle in 257 cal and after spending hundreds on trying to get it to shoot, I changed the barrel to a Shilen and all problems went away.

The only Wby I will ever own again is the Vangard.

I have loaded for two 25-06 rifles,and neither was at all difficult to get to shoot under 1" consistently.I did own two Mark V weatherby rifles,and neither would shoot under 1" consistently.

I currently own six Weatherbys. Four Mk Vs & two Vanguards. All of them shoot consistently under 1" and closer to 1/2". Go figure. jorge

About a year ago, someone made a posting about a magazine article having to do with accuracy testing factory, production built, rifles. The test involved most of the popular made rifles that are avaialbe to us here in the States.
Low and behold, THE most accurate rifle turned out to be a Weatherby, not a Savage as I would have guessed.
So, I found a Weatherby Vanguard in 223 on sale at my local gun store, and bought it. Turns out, it is extremely accurate, shooting many 3 shots groups at 100 yards that measure 3/8", with a 20 x scope I use for load developing.
Then, I bought another Weatherby Vanguard in 25-06. My first outing produced two heavy bullet groups that measured slightly less than 1/2" at 100 yards. These two groups, out of eight groups I shot, were with Speer's 120 grain bullets, with H-4831SC and RL-22 powder.
Yesterday, I went out again with the 25-06 and 6 different loads using 7828 powder that a guy recommended on another forum. Out of the 6 groups, two measured 3/8" for 3 shot, using a Weaver V-16 set on 16x. The bullets that shot best yesterday were Sierra's 120 grain and their 117 grainer. Life is good, with the Vanguards moving to center stage.
I seat bullets .010 off the lands, and seat bullets with Wilson Seaters for all of my rifles, except for the 30-30.
A buddy of mine has a Weatherby Vanguard in 300 Weatherby Magnum, and we shot it last week and got similar accuracy as above, but with reduced recoil loads.

VIVA Weatherby.

Don

Back to the basics, check your bedding, scope mounts, scope. Next is pick up some H4831 sc with win brass, win lg primers and 120 gr hp hornady or 100 grain hornadys. Start reloading and see if that improves anything. 25.06 is a very accurate cartridge. Esox357.

quote:

Originally posted by Jon2:
Thanks Fellas

The dies are not the same ones whch I used on the previous rifles. They were both RCBS though.

Scope is 100%.

I have tried factory ammo and amazingly I got a first group of about .6 and then every group thereafter was about 1.25 to 1.5

The factory was Winchester 120 grn PEP.

Thanks again

Jon,

You've got a lot of advice. Good luck solving this one. Please remember when you figure it out to come back and post the solution(s) that worked so we all can learn from this.

what type and manufacture scope did you say you had on the rifle?

The 25/'06 is "over bore capacity" for the .25" bore. Therefore, it is bound to be more finicky as regards accuracy with many powders. You will probably find a load it likes eventually, but it is easier to find a good load for a 250 Savage!

I will definitely post the results for everyone's benefit as I progress with load development and potential accurizing techniques.

I haven't got to the riflesmith yet for him to scope the barrel. Neither have I had time to get to the range again yet but whenI do any or all of these things I will update the post.

As I say I am determined that this one does not slip away like the previous ones have.

Scope is a S&B 3-12 x 50 illuminated. I took it off a Sako 75 in .308 before putting it on my Accumark and groups were consistent quarter inch with it's pet load so the scope is A ok.

Thanks again

Dear all

Thought I would update this thread as yesterday my brother and I went down to the range to continue developing a load for this rifle under the instruction of our good friend and reloading guru.

Basically, I now have got the load specified above consistently performing in the .5's/.6's.

It was a primer issue. I tried the follwing primers in rotation: Fed 210 M, Fed 215 M, CCI BR2, CCI 250 Magnum and Rem 9.5 M using the same load so just to recap AA3100 55 grns and 100 grn Sierra Pro Hunter.

The BR2's were the ones that finally got me a consistent shooter.

To begin the story properly, this is how we went about it.

Firstly as I said, I wanted my smith to check out the bore with his scope. The bore was good with no obvious signs of anything untoward. There was some carbon fouling in the throat area which was removed with solvent, JB shine and then more solvent with a bronze brush and then patched out dry.

We then started with completely new brass (Remington in this case). We went back to basics to eliminate all variables. This meant trimming the cases (even though brand new) to the length of the sortest one. We then checked each one for case neck concentricity. Any that were more then 2 thou out were discarded for this test.

We then took the box of bullets and batched them to get bullets which were the same length from the ogive. We formed 3 batches with about 12 which were way out. We discarded these for this purpose.



Next job was to prep the cases fully, lube them up and then load them up. We weighed each charge of powder as opposed to just throwing it out from the Harrel. This picture is of my brother and our good friend the guru starting to load them up.



We started with 3 rounds of each primer type.

Ok then down to the range to test.



This is what the result was with the first test



It seemed that the CCI 250 Mags were giving the best groups but remember I had put in a stunning group with this rifle before only to be disappointed when following up with another to check consistency. This is what happened with the CCI 250's. The CCI 250 group was in the 4's, the BR2's and Rem 9.5's were in the 5's.

The BR2's and the CCI 250's giving the best performance. Using the same cases but re-sizing, cleaning and trimming again, I reloaded 6 using BR2's and 6 using the 250's.

This was the result (BR2's at the top and 250's at the bottom.



I was delighted with the BR2's and have settled on this load for now. I think the 250 initial group was a fluke as on the second test you can see two holes touching and then one out. For whatever reason I reckon on the first group which was in the 4's, I just got lucky with the 3rd shot for some reason.

So all in all I had 3 groups with the BR2's which on aggregate measured in the .6's. I am completely happy with this, as this rifle will be used for Fallow, Roe and Muntjac at conventional ranges and will be my go to rifle this season.

However, I am thinking now that this rifle has even more potential and am intending to do some more development still using BR2's but looking at using 117 grn Pro Hunters as these had shown the same pattern of 2 together and one out with the Fed 210 M's which seems indicative of using a primer the rifle doesn't like.

Finally just a couple of pics of the rifle.





Hope you enjoy the story.

Hey! That reloading bench looks like mine.....except for the bars on the windows.

Glad you found the solution. I love Weatherby's and have owned 10 or 12, have seven at the moment. All shoot Weatherby ammo like a dream. It is difficult to find the combo that will equal the Wby factory ammo, but it is out there.

Great report....Thank you.......Tom

To tell the truth, I don't see how what you were\are going through makes the 25-06 a 'problem child.' Oh sure, some folks luck into a good recipe right off the bat. But your amount of testing shouldn't be considered untoward.

My 25-06 BDL is one of the first made by Remington. It began by shooting 1.25" to 1.5" groups with several bullets. I was not happy with this because several other 700s that I owned then shot much better. I rolled my ammo across the bench one day and noticed a lot of run out in the bullet. I checked out the dies and loaded a few dummy rounds. Same thing. I notice the seater stem seemed to wobble a little as I unscrewed it from the press. I took the seater to work and chucked it in a lathe and the entire die appeared to have been crooked.
I shipped bullets, brass and the die set back to the die manufacturer. They shipped back a new set of dies. They produced straight ammo.
My rifle began shooting 5 shot groups in the 5/8" to 3/4" range. I use Winchester brass, 100 grn Sierra Flat base bullets made long before they were called Game Kings, 210 Federal primers and 52 grn of IMR 4350. The bullet are seated to just touch the lands.
It is a mild load and is very consistent.

My observation of your setup:

Your shooting bench does not look really solid.
You have something on the muzzle of the rifle that can affect grouping. It is on in one photo and not in the others.
The bipod is not a very good way to test your rifle especially one with some recoil. Your fore end is probably bouncing with every shot.
Your results would be better with a bench rest type front rest with your off hand holding the fore end on the rest. With your off hand supporting the fore end you can more easily monitor how much pressure your face is putting on the stock. After a while people get where they are leaning their face on the stock to help steady it. That in turn affects recoil and groups produced by the rifle.

Thanks fellas

Onefunz I agree entirely. I think I had grown a little paranoid with .25-06 as the previous rifles I have had in this calibre have all shown similar patterns when developing a load. Guess what I only ever tried Fed 210 M! I do rate the Fed primers obviously and I use them in other rifles with excellent results it's just that I am slightly embarassed as I know that the primer can make a big difference but you tend to want to believe that they will work in all rifles you use. I call it the "I want to believe factor".

The guy that reminded us of the fact it could be the primer quite often does this test when dialing in a new rifle. Then when the rifle shows a particular preference for a certain primer he then concentrates on the other component parts.

SR not sure if you have missed the point here but the rifle is now shooting. It is a ASE Utra Jet Z Compact mod on the end which more than often actually enhances accuracy. I never shoot a rifle without one these days. The bench is 100% rock steady as the legs have sunk into the mud. I do however take your point about the bi-pod although have never found this to detract from accuracy with other rifles but I do occasionally wonder from time to time about this.

Thanks again

Jon

Glad to see you got it figured out Jon. I just love Accumarks .

quote:

Originally posted by Tapper2:
I love Weatherby's and have owned 10 or 12, have seven at the moment. All shoot Weatherby ammo like a dream. It is difficult to find the combo that will equal the Wby factory ammo, but it is out there.

I have 2 Weatherbys that I reload for, 338-378 and 257, that I have been able to easily obtain factory velocities on. I use IMR-7828 for both but the only problem with it is that it's fairly temperature sensitive. Simply varying the charge for cold versus hot temps works very well however. 7828 seems to be just the right burn rate for these two being just a bit slower then MRP/RL22 and a touch faster then MRP2/RL25.

Ken....

Cheers Heat

Just responded to your post on the other forum

quote:

SR not sure if you have missed the point here but the rifle is now shooting. It is a ASE Utra Jet Z Compact mod on the end which more than often actually enhances accuracy. I never shoot a rifle without one these days. The bench is 100% rock steady as the legs have sunk into the mud. I do however take your point about the bi-pod although have never found this to detract from accuracy with other rifles but I do occasionally wonder from time to time about this.

Hi Jon,
Almost anything that can be variable will degrade your accuracy. I noticed your rifle was shooting better but you are only shooting 3 shot groups and even they tend to vary some.
If you have never tested a rifle from a really solid bench rest you would find that your results will be better than the bipod. You are talking about small fractions of an inch.
Five shot groups, a heavy solid cast iron rest with a good set of sand bags and no gadget on the muzzle might give you a better indication of the true accuracy or your rifle. With the heavy rest you will be able to hold the fore end of your rifle which will help considering the recoil of a 25/06. If you want to be truly impressed try 10 shot groups at 200 yards.