My Jump to the Lands…?

[mpheithoff]

My Jump to the Lands…?

Cal: .243win
Action: Mauser 98
Make: Firearms International Corp. Washington D.C.
Hornady Lock-N-Load Straight O.A.L. Gauge
Threaded Modified Case .243win
Bullet: Hornady Varmint 75gr HP
B.O.L.: 0.979
Length from base to Ogive: 0.417
Ogive to Tip: 0.562

What I did:
1. Remove the bolt
2. Thread modified case onto OAL Gauge
3. Place bullet into Modified Case
4. Press gauge into chamber
5. Advance push-rod until the bullet meets the Lands
6. Tighten thumbscrew
7. Remove and measure

My Problem The bullet comes completely out of the modified case. And the push-rod protrudes out of the case about 0.02.

My Question: Is it unusual to have a jump to the lands that far?
Or did I do something wrong?

This is the first rifle I have ever done a load development on… or attempted to that is.

 

[Raven 6]

Re: My Jump to the Lands…?

Are you putting pressure against the modified case in the chamber? If so and it's not moving when you advance the bullet and tighten the screw, then you have alot of freebore, and the only thing you can do about that is set the barrel back (or replace barrel)and have it finish chambered again.

 

[mpheithoff]

Re: My Jump to the Lands…?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Triple 6</div><div class="ubbcode-body">Are you putting pressure against the modified case in the chamber?
<span style="color: #FF0000"><span style="font-weight: bold">YES</span></span>
If so and it's not moving when you advance the bullet and tighten the screw, then you have alot of freebore, and the only thing you can do about that is set the barrel back (or replace barrel)and have it finish chambered again. </div></div>

<span style="color: #FF0000">What about longer bearings on a larger o-give, 100gr VLDs or something similar?</span>

 

[Country]

Re: My Jump to the Lands…?

Mate I would just put the OAL gauge away and do it the simple easy way. Set up your seating die then make up a dummy load just a case and the projectile you are going to use. No powder or primer.
Seat it long so it may engauge the lands if it does blacken up the bullet with a marker pen and keep seating ita bit more ata time and chambering it untill it is just off the lands for a hunting rifle . This dummy bullet can then be used to reset your seating die if you move it at any point.
make sure that the bullet has a good amount of its shank into the case neck so it will seat straight and stay straight while feeding the ammo.
If the bullet does not get anywhere near the lands then your only option is to make sure it fits the magazine properly and is seated into the case neck enough to assure concentric seating.
Whatever jump results is what you have to put up with.
Remember good concentric bullet seating is also important to accuracy especially if you are not into the lands.

 

[Raven 6]

Re: My Jump to the Lands…?

Well he has already said the bullet come out the end of the case, so your dummy round isn't going to help him any. Yes you could go to a heavier bullet and that might help some, but as stated earlier, you don't want to use a OAL that will not fit into your magazine, and if you do not have the right twist in your rifling a heavier bullet might not stablize very well. But give it a try and see, but I still believe you have to much freebore to overcome. You don't want the bullet free from the case before it makes contact with the rifling, and that's what you have at this point.

 

[Country]

Re: My Jump to the Lands…?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Triple 6</div><div class="ubbcode-body">Well he has already said the bullet come out the end of the case, so your dummy round isn't going to help him any. Yes you could go to a heavier bullet and that might help some, but as stated earlier, you don't want to use a OAL that will not fit into your magazine, and if you do not have the right twist in your rifling a heavier bullet might not stablize very well. But give it a try and see, but I still believe you have to much freebore to overcome. You don't want the bullet free from the case before it makes contact with the rifling, and that's what you have at this point. </div></div>

Not sure what you are talking about but the dummy load has nothing to do with the threaded case or the OAL gauge its a seperate idea.
It is going to help because it has worked for 100 years before any gauges of any kind were ever invented .
It is a way of discovering where your lands touch the ogive of the bullet or if in fact you can even get that bullet to the lands. Also it tells you if the ammo with that seating depth will infact fit in the magazine by just trying the dummy cartridge in the magazine.

 

[Raven 6]

Re: My Jump to the Lands…?

What I am saying is that he already has a way of checking his over all length (OAL Gauge), the only thing he may need a dummy round for is to make sure it will work in his magazine. And if he has a pair of calipers to measure the length of his magazine, he want need it for that either. You say to use a case and projectile that you are going to use without powder and primer, basicially that's what an OAL Gauge is.

 

[Fuzzball]

Re: My Jump to the Lands…?

"Is it unusual to have a jump to the lands that far?"

No.

Seat your bullets a caliber deep and develop your load. Then experiment by moving in AND out in 5 thou steps to find the OAL that shoots best.

 

[Mag 300]

Re: My Jump to the Lands…?

if you have rechecked it go with it .
suggest you perform the OCW test to get close in that the in and out is one of the last items I use to tune .
Bill

 

[Greg Langelius *]

Re: My Jump to the Lands…?

Some rifles (and this apparently includes yours) have long throats.

Basically, such conditions force allowances in seating depths.

The first such allowance is that it becomes impractical to try to establish a short bullet jump to the rifling.

Now this can be frustrating on a theoretical level, but it doesn't necessarily mean that accuracy will be so badly impaired.

In these circumstances, I would abandon efforts to establish an OAL or bullet seating depth based on jump, and concentrate on making the round feed from the magazine at the longest practical OAL. Industry spec suggests that 2.710" should be the upward OAL limit.

At that length they <span style="font-style: italic">should</span> feed from the magazine reliably, and still provide the shortest jump possible. When measuring OAL for mag feeding purposes, measuring actual length, rather than lengths interpolated off the ogive, is preferable.

While this is not a reliable rule, often one will find that even though there's an uncomfortably long jump to the lands, well made ammo can still shoot rather well.

Greg

 

[mpheithoff]

Re: My Jump to the Lands…?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Country</div><div class="ubbcode-body">Remember good concentric bullet seating is also important to accuracy especially if you are not into the lands.
</div></div>

To get good concentric bullet seating, is that all in the neck preparation? Trimming, champering, using a ball expander?

 

[Country]

Re: My Jump to the Lands…?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Redneckmedic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Country</div><div class="ubbcode-body">Remember good concentric bullet seating is also important to accuracy especially if you are not into the lands.
</div></div>

To get good concentric bullet seating, is that all in the neck preparation? Trimming, champering, using a ball expander? </div></div>

No . Its a whole lot of things all working together.
You do need good straight necks internal and external.
The case has to be straight and have little difference in wall thickness.
Squaring the case head helps also .
The fireforming has to be right in the center of the chamber. Minimum spec chambers help by drasticly reducing the amount the case has to expand in the chamber .
The neck wall thickness needs to be accurate via neck turning .
Trimming the case mouth square is required.
An accurate chamfer inside is required .
Bullets with nice square bases helps also.
Even hardness of the neck area is also very helpful
A quality accurate BR seating type die is also required.
Testing for run out is desireable to confirm results and put aside rounds with excess runout .
A good press technique that supports the bullet verticle as it enters the die and you only seata short way then withdraw and without removing the case rotate 180 and seat all the way . This is less important with High quality BR dies.
Correct neck tension that assures that the projectile stays straight as it seats and also as it is chambered , but not excessive neck tension for the intended purpose .
Good quality BR type neck sizing dies that do a straight job with no expander ball type dies. Try Bushing type dies or even a Lee collet die.
A straight chamber in the gun.

Draging an expander ball through a case neck is sure to put the necks out of line with the case body .
Also it work hardens the brass unevenly .
For a bolt gun.
The best way to preserve that fireformed fit of your case in the chamber is to avoid Full length sizing in one go. Unless the dies are quality bushing type dies like a Redding .
I prefer to seperate the two sizing operations , neck size with a bushing and body size with a body die.
This way you can do minimum sizing of the case body to just go back in the gun. Your fit is not throw all out of whack by an old fashioned full length die that usually oversizes.
What I did many years ago was cut the tops off my old full length dies and turn them into what is now called a body die.
I still have a few laying around some place however you don't need to do that now .
Redding , Foster and others sell everything you need.