Throat too long?

[Sirshredalot]

Hello all

New guy here.

Ive got a rifle that just wont shoot the way that i want it to and i cannot get bullets to the lands.
Also seeing very high es numbers(100-250fps) and im pretty sure my loading procedure is sound.

My max magazine length is 3.425ish and i would have to seat bullets out to 3.452ish to reach the lands.
Bullets are a 150gr lapua scenar l, and a nosler custom competition 168gr.

The cartridge in question is a 280ai in a shilen stainless match/savage 110.

Does this sound normal or is my throat too long?
Ive got the ackley reamer print but am having trouble making sense of it.

Any advice is welcome
Please and thank you
Shred

 

[HTSmith]

My $.02--something sounds out of whack for sure. Your throat may well be long, but I doubt that's the whole source of the high ES and (I assume bad grouping). .025" off the lands is not that far in the scheme of things. In any case shortening your throat is an expensive set back job. Some things to try that I can think of:

• Seat some loads to within .010" of the lands and single load them while testing. If you get a huge improvement you've proven your theory.
• Try some different bullets--maybe hunting bullets. I've had Nosler Ballistic tips shoot better than match bullets in a couple of rifles.
• That kind of ES still makes me think something could be wrong with the loads. Are you using a powder that gives good case fill? Do you have adequate neck tension?

Just some things to think about. Best with it.

 

[Sirshredalot]

Case necks are consistantly .002 in tension.
Powders are rl23 and h4831sc dropped and trickled, then verified across two scales.
Loads give about 95% case fill id guess, maybe less because i have to seat the bullet out so far.

Case are all annealed after every firing, trimmed and prepped to be within 2 to 3 grains of each other. Vld chamfered and deburred after trimming to length.
Cases are neck sized in a lee collet die.
Bullets are seat with a hornady 7mm floating die.
Ive even had my chronograph warrantied because of my doubts.

Ive tried five different primers and 5 different bullets including
speer 130 soft point
Speer 145 match
Lapua scenar l 150
Nosler custom comp 168
Nosler rdf 185

The custom comps and the scenars post the best groups, so i bought more of them.

The most recent 8 shot group at 270 yards was 3.508", 3.010 if i toss the flyer.
212fps es, velocity average of 2953.
2957fps average theowing out the extreme high and low giving a 125fps spread.

Rifle is bedded into a mcmillan stock with pillars and devcon, barrel flly floated from lug forward.
Groups shot from a bench with front and rear bags.

My budget built $700 ar shoots better groups.

Shred

 

[dmoran]

Those are horrific velocity spreads.....

How are you throwing/dispensing your charges and how are you weighing them?
Are you using mixed brass?
How are you sizing your brass and to what relationship of the chamber?
Does your bolt closer feel the same on every round and is it effortless?
After firing, does your bolt open harder on some then others?

 

[46and2]

My Weatherby barrels have .375" (3/8") freebore and getting 15 fps max ES.

Sounds like something else.

 

[Sirshredalot]

Powder is dropped with a uniflow about 2 grains low the trickled with a redding.

The first scale is a hornady digital bench scale that is the verified on a dillon dterminator. Every load is weighed at least twice...usually 4 times getting the ballance right.

Cases are only ever neck sized because the bodies just dont grow.
Im working with the same lot of 50 hornady 280 remington brass and 50 winchester nickel plated brass that were all bought new.

I primarily use the hornady brass because the case volume is larger and i havent lost a primer pocket yet...some cases have 12+ firings.

Bolt always closes easily just like it should unless im fireforming.

Shred

 

[dmoran]

Something is seriously off.....

Check the chronograph - by shooting something else over it (like 22LR or 17HMR, etc.. with velocity specified ammo)
Check scale and all equipment for possible fault/error

Couple other possibilities:
Flash-hole issue (opened up to large <> or restricted by media, etc..)
Primers all seated to an equal amount of crush (not to much and not to little).
Case/powder contamination (from lube, foreign material, etc..)
Barrel inspection - borescope for issues

Personally have never seen "neck-sizing only" out perform full length sizing.
And have seen brass inconsistency issues arise in doing so.

Good luck with your endeavor.....

 

[243winxb]

Stop trying to reach the rifling. Seat bullets so the bullet shank is in full contact with the case neck. Shorter COL. Minimum .002" neck tension.

Use a magnum primer. Doing both will help H4831 burn better.

If you dont need to fl size after 12 loadings, the powder charge is to light, producing low pressures. More pressure, better powder burn. Nothing wrong with fl sizing when bumping the shoulder back the minimum.

 

[Sirshredalot]

I appreciate all the replies so far, thank you.

I have no way of adjusting primer crush? I use an rcbs bench prime...theyre all below flush. How do i measure that?

I have federal gold medal match magnum primers and it is primarily what i use, but winchester lrp gives a better es when i get a good one.

As far as pressure, ive run up to 61.5gr of rl23 to get heavy bolt and still havent body sized and the cases will fall into the chamber.

My "go to" load is 59 to 58.5gr h4831sc with a 150gr and gives me higher than book velocity...i think im running at the upper end of the pressure range?

Shred

 

[243winxb]

As far as pressure, ive run up to 61.5gr of rl23 to get heavy bolt and still havent body sized and the cases will fall into the chamber.

My "go to" load is 59 to 58.5gr h4831sc with a 150gr and gives me higher than book velocity...i think im running at the upper end of the pressure range?

Yes, hard bolt lift would seem to be high pressure, unless the bullet is moving to soon, causing a secondary pressure spike? i would think 65,000 psi would need brass fl sized?

Sorry, not much help. Good luck.

 

[Sirshredalot]

Maybe im missing somthing...im not trying to say that anyones elses ideas are wrong.
Im willing to consider it all.

Why are my cases not expanding once fired?
Why do they not need a full length size?
I bought a fl die in anticipation of this, but so far havent needed to use it.

What brass inconsistency are we talking about?
What do i look for?

Let me walk through my loading process and see if im missing somthing.

Once fired case come out of the tumbler
-anneal
-decap in a universal decapping die
-clean primer pocket(inspect for corn cob)
-neck size
-measure case oal, trim if needed.
-prime
-drop powder, trickle, verify across two scales.
-dump powder into case via funnel
-set and seat bullet to desire oal.

Talk to me about primer crush.
I use a bench prime and it has quite a bit of leverage. My primers are alway below flush.

Can the be "too" crushed?

Please and thank you
Shred

 

[Sirshredalot]

This is my most recent group posted earlier

 

[Dusty Stevens]

Thats some awful wind or small/broken scope. A factory gun with factory ammo rarely shoots that bad

 

[Sirshredalot]

Vortex viper hs lr, ususlly on 8x at 270 yards

 

[Sirshredalot]

Hmmm...i never thought about the scope being defective.

How would i verify this?

Shred

 

[243winxb]

Vortex viper hs lr, ususlly on 8x at 270 yards. The most recent 8 shot group at 270 yards was 3.508", 3.010 if i toss theflyer.

With the scope on 8 power, i would test at 100 yards and use a smaller aiming point.
The scope seems to have a fixed Parallax? "Setting 50 yards to infinity"? Not good for long range , if fixed.
Wind flags should be used.

Not bad accuracy at 3" and 270 yards using a scope on 8 power.

 

[Bc'z]

Vortex viper hs lr, ususlly on 8x at 270 yards

1st, Crank your magnification up when shooting off bench and testing. YOU CANT HIT WHAT YOU CAN'T SEE!
2nd, you stated seating to overall length
Use a comparator and measure brass base to shoulder to check for consistency in cases.
Then seat your bullets to a consistent cbto
Cartridge base to ogive.
3rd, look at bullets with a tangent ogive.
With a long free bore you'll have problems getting touch with a vld style bullet.
4th, Don't be afraid to jump a bullet.
Looking at your target you have a water line.
I'd work on a seating depth test with that load.

 

[ronemus]

Primer crush is a matter of feel - with a good priming tool (not a press) you can feel the primer contact the bottom of the pocket, then yield slightly. The objective is to have the anvil in contact with the pocket and the pellet of priming compound, without breaking the pellet. The best priming tool for feel is the Sinclair, although it's a bit salty at more than $100 and you have to put each primer in the tool manually. I modified an RCBS APS strip tool by putting in a much lighter return spring and the feel is adequate. If you prefer a bench-mounted tool, RCBS makes a bench version of the APS tool. A press has far too much leverage to really feel the primer seat.

The muzzle blast, especially from larger cartridges like the .280, can affect the chrono screens. The first screen should be at least fifteen feet from the muzzle. Gases and unburned powder can reach the first screen before the bullet, resulting in erratic triggering and sometime erroneously high velocities. Lighting can also mess with the screens, so I use IR screens and block ambient light (cardboard glued to the top of the diffusers - much less bother than a coffin).

Insufficient bullet pull (the force required to remove the bullet from the case neck) can cause large ES. I'd recommend seating bullets at least 0.2" into the neck and ignore jump for the moment - you'd be surprised how far bullets can jump and still perform well.

Is the barrel twist fast enough for stability (Sg >1.5)? It would be a good idea to measure the twist just to be sure it's what you think it is. There is a good stability calculator on the Berger web site; beware of some others that use simplistic calculators. The JBM calculator is another good one, as is the one in RSI's Shooting Lab.

 

[Sirshredalot]

If i recall correctly the twist is a 1:9 which should be more than enough for a 168gr.
Dont know about the 185 rdf.

I have consistently tried to set my chrono 12ft from the muzzle simply because thats is what the depth of my garage will accommodate.

I use the led light strips with the chrono and typically cover to top with a piece of cardboard.

Perhaps a bit more distance might get me better results.

I did a 50 round test with a 22lr rifle and believe i had about a 50fps es on this chrono.

Thank you all for the reposnses. This a great forum with great people. Thank you for you help...it is however 24 degrees here right now so results will come slowly.

Shred

 

[ebb]

When you load is the ceiling fan running in the room?