Need some help on group improvement 6PPC

[Chet58]

I am new to benchrest shooting so pardon the newbie guestions. I am shooting a 6PPC which I purchased used, third hand actually. I do not know the round count, but I believe it is fairly low. Supposedly the gun was built by Bob White. Barrel is a Broughton, I believe the action is a Time Precision and the trigger is a Jewell target at about 2 oz. I am using Lapua brass preped with a .008 neck wall, 27.1 grains of N133 and a Berger 68gr FB-HP bullet. Cases have been fire formed to the barrel and fired a few more times.

I am shooting a fair group at 100 yrds of .324 but will have at least 1 flyer in the group taking it up to .51 or better. Since I have only a couple hundred rounds total under by belt I don't know if this is me, my case prep, the gun, my load, my clean, the conditions or it is completely normal. My best 5 shot group to date is a .275 so I know the gun should be capable of at least that in calm conditions. I am preloading before I go to the range and log everything I can think of. Round to Round I believe I am extremely consistent in my preparation.

Any light a more experienced shooter can shed on this would be a help. I am a little frustrated with my performance but I absolutly love this sport.

Thanks

 

[L-46]

Chet,
It is a great sport,
with out seeing your setup, are the fliers all over or in a similar place?
few things to check, flag set up
bags/ rests, and set up of bags, does the gun recoil straight and return to aim point?
a trip to your local BR range on comp day and talk with some there may help,
Good shootin
L-46

 

[LHSmith]

Get away from N-133, it's too much of a learning curve for a newby....and forget about pre-loading with N-133. Try a light to moderate load in H-322, or LT-32.
Also,wind flags are a must and learn from them and mirage as well to shoot small. A mirage shield on the barrel is also a prerequisite.

 

[Tim Singleton]

Finding seating depth your gun likes with the bullet you are using is pretty high on the list of where to start watch Jack Neary tuning videos on youtube even using h322 or lt32 the method of finding the powder charge and bullet seating depth stays the same

http://www.targetshooter.co.uk/?p=1024

One question on the flyers. Does the round feel different when you close the bolt?
What type front and rear rest are you using? What type sizing die?

Maybe Boyd Allen will chime in here

 

[artbosco]

I am new to benchrest shooting so pardon the newbie questions. I am shooting a 6PPC which I purchased used, third hand actually. I do not know the round count, but I believe it is fairly low. Supposedly the gun was built by Bob White. Barrel is a Broughton, I believe the action is a Time Precision and the trigger is a Jewell target at about 2 oz. I am using Lapua brass preped with a .008 neck wall, 27.1 grains of N133 and a Berger 68gr FB-HP bullet. Cases have been fire formed to the barrel and fired a few more times.

N133 likes a lot of neck tension. In the .003" to .004" range. Work your way up, however there are two good nodes for the 6PPC. One around 29.0 to 29.4 grains and the other around the 29.8 to 30.0 grains [top end]. My barrel prefers the low 29s. No need to shoot too hot. I'm currently using 29.1 with a .257" bushing. My previous barrel liked 29.4. It's chambered for a .262 neck. My loaded round at the pressure ring is .260", so with .257 bushing I'm applying .003" of neck tension. Lapua case is trimmed to 1.490". Using a Bart's 68 grain Ultra. Full Length size with a bushing die. Harrell's is a good source, with a good price. Broughton is a fine barrel. Shoot over wind flags. Buy a copy of Tony Boyer's new book The Book of Rifle Accuracy from Bruno's. It's the bible on the 6PPC. Have fun.

 

[jonbearman]

Your charge is on the light side.Make sure that your bedding screws are tight along with the scope mounts and rings to the bases.Do you use stock tape to allow the gun to move smoothly in the front rest and rear bag.

 

[Chet58]

Thanks guys that is a lot to digest.

Four things looks like they are simple fixes but basically starting over. 1.) Insure trim length is uniform. I was running 1.500 and have not checked the trim for growth since the original prep. Sounds like moving to a 1.490 length would be a good move. 2.) according to Jacks video I am running neck thickness on the tight side .0085 should be cut to .0081 ish for a .262 neck 3.) Powder. I have H322 just haven't run it yet. Sounds like a good time to start. I know N-133 can be a little more flukie for a newbie 4.) Bullet seating depth and tune the jam length. That should be enough changes.

Primer pockets do feel inconsistent when I am setting primers. Sounds like I need a primer reamer as well.

I do use a shade on the barrel for mirage.

I am using a Farley coax front rest and a Protector rear rabbit ear bag for the back. .005 UHMW tape front and rear. My zero does move around regardless of the rest I am using. I picked up the Farley for a fair price and I like the rest weight over my Caldwell BR. I do have to move the coax to move the cross hairs back to the point of aim after each shot. It is not a straight push back to the zero point. Should I increase the tension on the front bag? and to what point is enough? Also the Farley front bag doesn't wrap the stock. Should I switch to an owl bag instead to get a better grip on the fore stock?

I am also using Wilson dies. I do have a set of Redding Type-S Competition dies that came with the rifle, but have not been using them.

The most N133 I can get in a case is about 28.4 grains with some room left to seat the bullet. No way I could get 30.0. I have checked my weights on three scales and they are all running pretty close. Sounds like I have not fully expanded the cases fire forming.

 

[FergusBailey]

Chet

Are you actually using flags? If not, you need to start right now. If you are using flags, what type?

Can you get to a match? You will learn a LOT more by shooting with other benchrest shooters, than by trying to learn on your own. Odds are good that one or more experienced shooters will help you during and after a match. And that will really help you diagnose where you real issues are.

 

[LHSmith]

Trim length and case neck turning diameter are based on reamer design used on your specific chamber ....and there are perhaps hundreds of reamer designs for the 6 PPC. If you trim your cases too short for your chamber, you will likely get more of a carbon ring problem than normal. I would not touch the primer pocket...other than to scrape the residue out.....not with a reamer.
The Wilson dies are most likely neck sizers, and if running anything in mid to upper charge ranges will eventually cause problems. Avoid problems and send Harrels Precision 3 fired cases (call them on specifics) and get a FLS matched to your specific chamber....and use it every time.
If you don't shoot along-side other shooters that can cause your POA to move due to their muzzle blast, it is not necessary to have the ears in hard contact with the rest. If you decide to shoot comp., then adjust tighter....and leave it there. Not sure what you mean by the front bag "wrapping" the stock....there are only two makers of bags for Farley's and they both contact the stock consistently. (Edit-Possibly you have a Hunter Class stock (2-1/4 wide forend.....and your front bag is for a VFS stock (3" fore-end).....in which case Edgewood makes a 2" for the Farley) The rules of shortrange BR require that the rifle be able to be lifted out of the stock (i.e. -no clamping or restaint).
Bob White operates Shooters Corner...a store for used Benchrest items and also a gunsmith...call Bob and ask if he has the details on your chamber.
Get the Tony Boyer book.....it will be the best ~$40 you ever spent on the sport....it will save you hundreds in wasted components. Flags are an absolute necessity.......shooting in dead calm for optimum results is a BIG myth....shoot instead when the flags show exactly the same during a mild push when the mothball is not bouncing around.
The zero moving is most likely due to conditions....it is almost always typical at matches .....and what makes the game challenging.
Set your gun in the bags , sight on a target at 100/200 yds, come back and check the crosshair position in 1/2 hour increments throughout the day......and you will begin to understand what you have to deal with in attempts to get them all in the SAME exact hole.

 

[LHSmith]

Also, new brass tends to solve a lot of accuracy problems (the inconsistent primer pockets is a good indicator). Once you verify your chamber dimensions, precision turned brass can now be purchased from several sources. With the proper sizing die and Lapua brass, you can expect to get dozens of loadings with all but the hottest loads.
133 will be a nightmare for you.....you will shoot "lights out" in one session, then next time out you got a "train wreck"....which will have you guessing what went wrong....bad scope? missed condition? bad bullets? bag set-up? inconsistent powder charge?...etc.....etc..... (PS- It WAS the TUNE.....it came and went :'()
My advice is to work up a load in H-322 in light to mid charge range as found in the manuals and you should begin to shoot small groups almost boringly in good conditions while developing CONFIDENCE in your gun/ scope/ rest set up.
Now you can proceed to shoot in more challenging conditions and learn the effects of wind and mirage, experiment with different components, and learn the art of finding and keeping in a "TUNE" that will get you into the competition level.

 

[Tim Singleton]

LHSmith
Has offered up some very good advise here.

 

[EWaugh]

What about trigger control are you up against the stock applying pressure when touching the trigger. If so, maybe you are pulling your shots... Just thought to bring it up since trigger pull is a major role in all shooting disciplines. Good Luck! I enjoyed reading all the good replies.

 

[Chet58]

Fergus - I have flags but have not been using them consistently. This last sessions has shown me the error of my ways. Flags are two sided right-left with a trailing streamer and a spinner out front. I do not have a wind speed indicator.

LHSmith - Yes I am working on my own. Yes I am going to compete. Local match coming up in in July. I know the best place to learn is with other shooters but I am just getting some basics down before the real fun starts. I am not expecting to shoot in the 1's but I am up for the challenge.

Interesting comment on primer pockets. I listened to Jack Nealys videos and it sounded like he was sold on primer pocket prep being a key element. I started with new brass and have been trying to keep things seperated for how many times cases have been loaded upuntil my last session. When I primed cases I did note a lot of difference in installation force. Maybe a refinement for later.

Also I just ordered Tony Boyers book as well.

EWaugh - Thanks for the advise. I think I am doing OK in that department. I already have a feel for when I have blown the shot with a heavy hand /finger. I just release my grip completely and watch my sights and reset my aim point.....and breath.

Thanks for all the help this is all some really great advise.

 

[LHSmith]

The flag tails are the only wind speed indicator you need.....just monitor the tail angles. The daisy (spinner) aids in pinpointing the wind direction.

 

[FergusBailey]

Chet

Tony's book is excellent, and well worth the investment you are making there.

Definitely get out and practice with flags as often as possible. Dont shoot without them. The only way to learn to shoot with flags is to get out and shoot over flags. It starts off being meaningless, but comes together over time. Again, this is where a good mentor can really bring you up the learning curve, but you will eventually get it on your own.

 

[searcher]

TSINGLETON well advised on importance of depth adjustment - what works in your rifle. I have run into the "on-in-five-shot-flier" under a few circumstances that I did not see anyone touch on - so for my two cents;
1) When setting your seating depth very close to the lands (say within a few thou), unless each round is measured off the ogive for O.A.L., you will have a few further off the lands than the rest (usually not the cause of the wayward flier) and a few that will actually touch the lands and causes slightly higher pressure and often a flier. Use a measuring tool to KNOW what your actual distance to the lands is (or how far in) and be sure none can touch if you expect them to be off. I'd recommend at least trying light neck tension and seating bullets .010" long into the lands so they "soft seat". If you are not getting absolutely concentric loaded rounds, this can help a problem that will ultimately need to be fixed.
2) Custom rifles don't always have chambers that allow for the "maximum brass length" as advertised in loading manuals. On some rifles, one could assume he is well under the max brass length allowed for by having trimmed to "book" recommended trim length - only to later find that a few of the longer pieces of brass (even though they may only be .001" longer), can be pinching the bullet due to excessive length. While not likely - it happens enough to not discount it. A quick check by doing a chamber cast or other method will eliminate just another possibility.

Good luck and have fun. If you are lucky, this will take you the rest of your life.