TTSX jump: how much is too much?

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Fisher-Dude

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I'm looking to load some 150 grain TTSX's in a 308 Win, IMR3031 and RP cases. Rifle is a T3, known for long throat lengths and OAL-limiting magazines.

Here are the numbers that have got me running around Google far too much:

Hornady modified case and OAL gauge show my OAL to be 2.965" when the bullet contacts the lands
Barnes suggests starting at .050" off the lands, but a 2.915" cartridge isn't going to fit the magazine - 2.825" squeaks in and feeds
Barnes also suggests a 2.735" OAL for this combo, which would result in a 0.230" jump

Questions: is nearly a quarter inch of jump too much using Barnes' suggested OAL? Will lower pressures with this much jump affect velocities enough to hinder the "drive 'em fast" rule for reliable TTSX performance?

I've always had good success using book OAL's on other loads with other bullet brands.

I'll be using my Hornady comparator to measure ogives for consistent loading once I tie down a reasonable OAL. I've sampled the Barnes bullets and their bullet lengths are really consistent at +/- .0015".

I'm not too interested in using other bullet weights except as a last resort - I had enough trouble finding these ones!


Thanks in advance for your help!
 
Fisher-Dude said:
I'm looking to load some 150 grain TTSX's in a 308 Win, IMR3031 and RP cases. Rifle is a T3, known for long throat lengths and OAL-limiting magazines.

Here are the numbers that have got me running around Google far too much:

Hornady modified case and OAL gauge show my OAL to be 2.965" when the bullet contacts the lands
Barnes suggests starting at .050" off the lands, but a 2.915" cartridge isn't going to fit the magazine - 2.825" squeaks in and feeds
Barnes also suggests a 2.735" OAL for this combo, which would result in a 0.230" jump

Questions: is nearly a quarter inch of jump too much using Barnes' suggested OAL? Will lower pressures with this much jump affect velocities enough to hinder the "drive 'em fast" rule for reliable TTSX performance?

I've always had good success using book OAL's on other loads with other bullet brands.

I'll be using my Hornady comparator to measure ogives for consistent loading once I tie down a reasonable OAL. I've sampled the Barnes bullets and their bullet lengths are really consistent at +/- .0015".

I'm not too interested in using other bullet weights except as a last resort - I had enough trouble finding these ones!


Thanks in advance for your help!
Click to expand...

First Pat the real answer is you can only load to a MAX of 2.825 and be able to use your mag ! Second why does there have to be a TOO Far ? I load them to 2.800 out of mine with 45 gr 3031 or 4895 and they they shoot Very Well ! Both WELL over 2800 fps !
Cheers RJ
 
I feel like the only way to know whether the jump is too much is to try it. If they list 2.730 as the length they used in the book, I would expect you can use anything from 2.730 up to the max length of your magazine safely, so I'd pick a starting point that you like and see how it works out. If you don't like the results at 2.825 then try it again at 2.800, and so on.

These bullets are known to like a good jump.
 
Tikka makes the M+ magazine that allows an OAL of 2.95"

I would seat them to 2.88" OAL if you had the M+ mag, which puts .308" of bullet shank below the case mouth, and a jump of approx .085"

If you don't get an M+ mag, I'd seat them to 2.81" which will allow for some wiggle room with your OEM magazine length
 
Fisher-Dude said:
I'm looking to load some 150 grain TTSX's in a 308 Win, IMR3031 and RP cases. Rifle is a T3, known for long throat lengths and OAL-limiting magazines.

Here are the numbers that have got me running around Google far too much:

Hornady modified case and OAL gauge show my OAL to be 2.965" when the bullet contacts the lands
Barnes suggests starting at .050" off the lands, but a 2.915" cartridge isn't going to fit the magazine - 2.825" squeaks in and feeds
Barnes also suggests a 2.735" OAL for this combo, which would result in a 0.230" jump

Questions: is nearly a quarter inch of jump too much using Barnes' suggested OAL? Will lower pressures with this much jump affect velocities enough to hinder the "drive 'em fast" rule for reliable TTSX performance?

I've always had good success using book OAL's on other loads with other bullet brands.

I'll be using my Hornady comparator to measure ogives for consistent loading once I tie down a reasonable OAL. I've sampled the Barnes bullets and their bullet lengths are really consistent at +/- .0015".

I'm not too interested in using other bullet weights except as a last resort - I had enough trouble finding these ones!


Thanks in advance for your help!
Click to expand...


Every Tikka T3 I've owned/shot/loaded for has a long throat. The saving grace of these excellent rifles is that those throats are "tight"

This usually means you won't get the best velocities out of these rifles but you should be able to expect stellar accuracy, no matter which bullet you use.

Last Wednesday I had a fellow bring me a Tikka T3, blued model, in it's original factory stock.

He told me the rifle wouldn't shoot well. Not his handloads or factory Premium loads.

He was right his rifle/scope/stock combination wasn't shooting well.

It wasn't the ammunition, it wasn't the maintenance, all looked very good and better than most I've seen.

We checked everything, including a chamber cast, which showed that everything was concentric to the axis of the bore. Bit of a conundrum.

The rifle is chambered for the venerable 30-06 Springfield.

The owner didn't have a spare magazine so I used a spare magazine for my T3, 6.5x55.

After making sure the scope was ok by putting it on another rifle and making sure the bases/rings were solid etc. Even checked to make sure the recoil lug was making proper contact and that the receiver screws were torqued properly. All was well.

We took it to the range one more time, in the hopes that whatever was causing the issue would show itself.

The first three shots of Federal Premium went into an eight inch group. So, my turn at the rifle next.

Put in the spare magazine and the next group of three was around an inch. Big surprise.

The owner of the rifle is a decent shot and the rifle is about 5 years old and has always shot well.

It dawned on both of us that whatever was wrong was in the magazine.

I gave him my spare magazine and he went away happy, thinking I was a genius. NOT SO. I have no idea why that magazine is causing that rifle not to shoot well.

I used that magazine in my T3 6.5x55 and everything fed smoothly and the rifle shot well. Go figure.
 
bearhunter said:
Every Tikka T3 I've owned/shot/loaded for has a long throat. The saving grace of these excellent rifles is that those throats are "tight"

This usually means you won't get the best velocities out of these rifles but you should be able to expect stellar accuracy, no matter which bullet you use.

Last Wednesday I had a fellow bring me a Tikka T3, blued model, in it's original factory stock.

He told me the rifle wouldn't shoot well. Not his handloads or factory Premium loads.

He was right his rifle/scope/stock combination wasn't shooting well.

It wasn't the ammunition, it wasn't the maintenance, all looked very good and better than most I've seen.

We checked everything, including a chamber cast, which showed that everything was concentric to the axis of the bore. Bit of a conundrum.

The rifle is chambered for the venerable 30-06 Springfield.

The owner didn't have a spare magazine so I used a spare magazine for my T3, 6.5x55.

After making sure the scope was ok by putting it on another rifle and making sure the bases/rings were solid etc. Even checked to make sure the recoil lug was making proper contact and that the receiver screws were torqued properly. All was well.

We took it to the range one more time, in the hopes that whatever was causing the issue would show itself.

The first three shots of Federal Premium went into an eight inch group. So, my turn at the rifle next.

Put in the spare magazine and the next group of three was around an inch. Big surprise.

The owner of the rifle is a decent shot and the rifle is about 5 years old and has always shot well.

It dawned on both of us that whatever was wrong was in the magazine.

I gave him my spare magazine and he went away happy, thinking I was a genius. NOT SO. I have no idea why that magazine is causing that rifle not to shoot well.

I used that magazine in my T3 6.5x55 and everything fed smoothly and the rifle shot well. Go figure.
Click to expand...

Did he try shooting with the new magazine? Or you with the original? Otherwise I'm sceptical.
 
jethunter said:
Did he try shooting with the new magazine? Or you with the original? Otherwise I'm sceptical.
Click to expand...

Yes, he did try the new magazine and did well. He now owns that magazine and I have the one that was causing issues for his rifle.

It's fine in my T3. I'm hoping to get another look at his rifle.

The cartridges fed fine and the magazine fit snugly, without binding. There aren't any visible defects. It's a mystery to me. I'm missing something that's likely obvious.

I didn't post this to derail the OP's query. Just wanted to throw it in because he may run into a similar issue.

Every once in a while someone complains about their Tikka T3 not being accurate. That 30-06 was the first T3 I've shot or seen with accuracy issues that weren't easy to assess the reason. Most of the time, it's shooter error or scope issues.

I could see a problem if the magazine lips or floorplate showed extreme wear. It looks fine and the spring keeps everything tight and level.
 
Interesting that a magazine would apparently change accuracy.

I've been shooting Swift Sciroccos from this T3 since I got it. Accuracy has always been sub-MOA, typical of Tikkas. I have 3 mags for it, doesn't matter which one I use.

It's outfitted with a Conquest MC that I bought from a renowned Ballistics Super Genius. I wish they still made those scopes!
 
Fisher-Dude said:
Interesting that a magazine would apparently change accuracy.

I've been shooting Swift Sciroccos from this T3 since I got it. Accuracy has always been sub-MOA, typical of Tikkas. I have 3 mags for it, doesn't matter which one I use.

It's outfitted with a Conquest MC that I bought from a renowned Ballistics Super Genius. I wish they still made those scopes!
Click to expand...


Same with my T3 6.5x55 and it's not fussy about bullet makers or weights.

This is a mystery to me as well. That's why I would really like to get another look at the offending rifle.

The T3 30-06 will likely shoot hand loads better than the Federal Premium 165 grain offering. It's all he had at the time.

I was hoping someone here might have had a similar experience and found the reason.

Once that cartridge is in the breech and locked in, nothing else, that isn't obvious should be affecting the flight of that bullet. That's just about a given, as long as the bedding/scope/mounting is good.
 
jethunter said:
That's a new one for me. I am not knowing how the magazine affects the accuracy of a chambered round.
Click to expand...


I've had it happen with poorly fitted Lee Enfield No1 and No magazines. But they were quite obvious.

Thanx for thinking about it. I do appreciate the effort.


I was thinking that the magazine was somehow contacting the bolt?? I won't know until I get another look at the rifle. There are no rub marks that shouldn't be there to indicate this and the 6.5x55 cases have a larger diameter than the 30-06????
 
How does a magazine influence accuracy at all though, I don't get it.. The magazines job is done once the round is chambered?! ..Is it like, messing with the resonance of the rifle or something lol, throwing off its chi?
 
The sear forces the cocked bolt to the top of the action tilting the lugs. A overly strong magazine spring does the same, and it's different every shot. Magazine lips that touch the bolt body can screw with your head.

If you have enough junk taking bad bounces and different landings weird #### happens. 8" to 1" is a lot though, I'd have to see it.
 
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